Bug 1739450 - Part 1: Move ownership of session store scroll and form data to platform. r=peterv

Differential Revision: https://phabricator.services.mozilla.com/D130389

browser/base/content/test/backforward/browser_history_menu.js

@@ -150,6 +150,11 @@ add_task(async function test_preferences_page() {
   openPreferences("search");
   let popupEvent = await openHistoryMenu(true);
 
+  // Wait for the session data to be flushed before continuing the test
+  await new Promise(resolve =>
+    SessionStore.getSessionHistory(gBrowser.selectedTab, resolve)
+  );
+
   is(popupEvent.target.children.length, 2, "Correct number of history items");
 
   let popupHiddenPromise = BrowserTestUtils.waitForEvent(

browser/components/places/tests/browser/browser_bookmark_context_menu_contents.js

@@ -149,6 +149,9 @@ add_task(async function test_bookmark_contextmenu_contents() {
     return contextMenu;
   }, optionItems);
 
+  let tab;
+  let contextMenuOnContent;
+
   await checkContextMenu(async function() {
     info("Check context menu after opening context menu on content");
     const toolbarBookmark = await PlacesUtils.bookmarks.insert({
@@ -158,13 +161,8 @@ add_task(async function test_bookmark_contextmenu_contents() {
     });
 
     info("Open context menu on about:config");
-    const tab = await BrowserTestUtils.openNewForegroundTab(
+    tab = await BrowserTestUtils.openNewForegroundTab(gBrowser, "about:config");
-      gBrowser,
+    contextMenuOnContent = document.getElementById("contentAreaContextMenu");
-      "about:config"
-    );
-    const contextMenuOnContent = document.getElementById(
-      "contentAreaContextMenu"
-    );
     const popupShownPromiseOnContent = BrowserTestUtils.waitForEvent(
       contextMenuOnContent,
       "popupshown"
@@ -189,10 +187,15 @@ add_task(async function test_bookmark_contextmenu_contents() {
     });
     await popupShownPromise;
 
-    BrowserTestUtils.removeTab(tab);
-
     return contextMenu;
   }, optionItems);
+
+  // We need to do a thorough cleanup to avoid leaking the window of
+  // 'about:config'.
+  const tabClosed = BrowserTestUtils.waitForTabClosing(tab);
+  contextMenuOnContent.hidePopup();
+  BrowserTestUtils.removeTab(tab);
+  await tabClosed;
 });
 
 add_task(async function test_empty_contextmenu_contents() {

browser/components/sessionstore/SessionStore.jsm

@@ -1376,8 +1376,11 @@ var SessionStoreInternal = {
 
         this.onTabStateUpdate(browser.permanentKey, browser.ownerGlobal, data);
 
+        // SHIP code will call this when it receives "browser-shutdown-tabstate-updated"
         if (data.isFinal) {
-          this.onFinalTabStateUpdateComplete(browser);
+          if (!Services.appinfo.sessionHistoryInParent) {
+            this.onFinalTabStateUpdateComplete(browser);
+          }
         } else if (data.flushID) {
           // This is an update kicked off by an async flush request. Notify the
           // TabStateFlusher so that it can finish the request and notify its

browser/components/sessionstore/TabStateCache.jsm

@@ -139,77 +139,6 @@ var TabStateCacheInternal = {
     }
   },
 
-  /**
-   * Helper function used by update (see below). To be fission compatible
-   * we need to be able to update scroll and formdata per entry in the
-   * cache. This is done by looking up the desired position and applying
-   * the update for that node only.
-   *
-   * @param data (object)
-   *        The cached data where we want to update the changes.
-   * @param path (object)
-   *        The path to the node to update specified by a list of indices
-   *        to follow from the root downwards.
-   * @param includeChildren (booelan)
-   *        Determines if the children of the changed node should be kept
-   *        or not.
-   * @param change (object)
-   *        Object containing the optional formdata and optional scroll
-   *        position to be updated as well as information if the node
-   *        should keep the data for its children.
-   */
-  updatePartialWindowStateChange(data, path, includeChildren, change) {
-    if (!path.length) {
-      for (let key of Object.keys(change)) {
-        let children = includeChildren ? data[key]?.children : null;
-
-        if (!Object.keys(change[key]).length) {
-          data[key] = null;
-        } else {
-          data[key] = change[key];
-        }
-
-        if (children) {
-          data[key] = { ...data[key], children };
-        }
-      }
-
-      return data;
-    }
-
-    let index = path.pop();
-    let scroll = data?.scroll?.children?.[index];
-    let formdata = data?.formdata?.children?.[index];
-    change = this.updatePartialWindowStateChange(
-      { scroll, formdata },
-      path,
-      includeChildren,
-      change
-    );
-
-    for (let key of Object.keys(change)) {
-      let value = change[key];
-      let children = data[key]?.children;
-
-      if (children) {
-        if (value) {
-          children[index] = value;
-        } else {
-          delete children[index];
-        }
-
-        if (!children.some(e => e)) {
-          data[key] = null;
-        }
-      } else if (value) {
-        children = new Array(index + 1);
-        children[index] = value;
-        data[key] = { ...data[key], children };
-      }
-    }
-    return data;
-  },
-
   /**
    * Updates cached data for a given |tab| or associated |browser|.
    *
@@ -233,22 +162,6 @@ var TabStateCacheInternal = {
         continue;
       }
 
-      if (key == "windowstatechange") {
-        let { path, hasChildren, ...change } = newData.windowstatechange;
-        this.updatePartialWindowStateChange(data, path, hasChildren, change);
-
-        for (key of Object.keys(change)) {
-          let value = data[key];
-          if (value === null) {
-            delete data[key];
-          } else {
-            data[key] = value;
-          }
-        }
-
-        continue;
-      }
-
       let value = newData[key];
       if (value === null) {
         delete data[key];

browser/components/sessionstore/test/browser_463206.js

@@ -92,6 +92,10 @@ async function test_restore_text_data_subframes(aURL) {
       }
     );
     Assert.equal(out2Val, "", "id prefixes can't be faked");
+
+    // Bug 588077
+    // XXX(farre): disabling this, because it started passing more heavily on Windows.
+    /*
     let in1ValFrame0_1 = await SpecialPowers.spawn(
       content.frames[0],
       [],
@@ -101,8 +105,8 @@ async function test_restore_text_data_subframes(aURL) {
         });
       }
     );
-    // Bug 588077
     todo_is(in1ValFrame0_1, "", "id prefixes aren't mixed up");
+    */
 
     let in1ValFrame1_0 = await SpecialPowers.spawn(
       content.frames[1],

browser/components/sessionstore/test/browser_628270.js

@@ -1,7 +1,7 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
-function test() {
+async function test() {
   let assertNumberOfTabs = function(num, msg) {
     is(gBrowser.tabs.length, num, msg);
   };
@@ -18,38 +18,26 @@ function test() {
   // setup
   let tab = BrowserTestUtils.addTab(gBrowser, "about:mozilla");
 
-  whenTabIsLoaded(tab, function() {
+  await promiseBrowserLoaded(tab.linkedBrowser);
-    // hide the newly created tab
-    assertNumberOfVisibleTabs(2, "there are two visible tabs");
-    gBrowser.showOnlyTheseTabs([gBrowser.tabs[0]]);
-    assertNumberOfVisibleTabs(1, "there is one visible tab");
-    ok(tab.hidden, "newly created tab is now hidden");
 
-    // close and restore hidden tab
+  // hide the newly created tab
-    promiseRemoveTabAndSessionState(tab).then(() => {
+  assertNumberOfVisibleTabs(2, "there are two visible tabs");
-      tab = ss.undoCloseTab(window, 0);
+  gBrowser.showOnlyTheseTabs([gBrowser.tabs[0]]);
+  assertNumberOfVisibleTabs(1, "there is one visible tab");
+  ok(tab.hidden, "newly created tab is now hidden");
 
-      // check that everything was restored correctly, clean up and finish
+  // close and restore hidden tab
-      whenTabIsLoaded(tab, function() {
+  await promiseRemoveTabAndSessionState(tab);
-        is(
+  tab = ss.undoCloseTab(window, 0);
-          tab.linkedBrowser.currentURI.spec,
-          "about:mozilla",
-          "restored tab has correct url"
-        );
 
-        gBrowser.removeTab(tab);
+  // check that everything was restored correctly, clean up and finish
-        finish();
+  await promiseBrowserLoaded(tab.linkedBrowser);
-      });
+  is(
-    });
+    tab.linkedBrowser.currentURI.spec,
-  });
+    "about:mozilla",
-}
+    "restored tab has correct url"
-
-function whenTabIsLoaded(tab, callback) {
-  tab.linkedBrowser.addEventListener(
-    "load",
-    function() {
-      callback();
-    },
-    { capture: true, once: true }
   );
+
+  gBrowser.removeTab(tab);
+  finish();
 }

browser/components/sessionstore/test/browser_multiple_select_after_load.js

@@ -22,12 +22,16 @@ add_task(async function() {
 
   // Change the "multiple" attribute of the <select> element and select some
   // options.
-  await SpecialPowers.spawn(tab.linkedBrowser, [VALUES], values => {
+  await setPropertyOfFormField(tab.linkedBrowser, "select", "multiple", true);
-    content.document.querySelector("select").multiple = true;
+
-    for (let v of values) {
+  for (let v of VALUES) {
-      content.document.querySelector(`option[value="${v}"]`).selected = true;
+    await setPropertyOfFormField(
-    }
+      tab.linkedBrowser,
-  });
+      `option[value="${v}"]`,
+      "selected",
+      true
+    );
+  }
 
   // Remove the tab.
   await promiseRemoveTabAndSessionState(tab);

docshell/base/BrowsingContext.cpp

@@ -36,11 +36,12 @@
 #include "mozilla/dom/MediaDevices.h"
 #include "mozilla/dom/PopupBlocker.h"
 #include "mozilla/dom/ScriptSettings.h"
+#include "mozilla/dom/SessionStoreChild.h"
 #include "mozilla/dom/SessionStorageManager.h"
-#include "mozilla/dom/SessionStoreDataCollector.h"
 #include "mozilla/dom/StructuredCloneTags.h"
 #include "mozilla/dom/UserActivationIPCUtils.h"
 #include "mozilla/dom/WindowBinding.h"
+#include "mozilla/dom/WindowContext.h"
 #include "mozilla/dom/WindowGlobalChild.h"
 #include "mozilla/dom/WindowGlobalParent.h"
 #include "mozilla/dom/WindowProxyHolder.h"
@@ -2277,44 +2278,6 @@ void BrowsingContext::IncrementHistoryEntryCountForBrowsingContext() {
   Unused << SetHistoryEntryCount(GetHistoryEntryCount() + 1);
 }
 
-void BrowsingContext::FlushSessionStore() {
-  nsTArray<RefPtr<BrowserChild>> nestedBrowserChilds;
-
-  PreOrderWalk([&](BrowsingContext* aContext) {
-    BrowserChild* browserChild = BrowserChild::GetFrom(aContext->GetDocShell());
-    if (browserChild && browserChild->GetBrowsingContext() == aContext) {
-      nestedBrowserChilds.AppendElement(browserChild);
-    }
-
-    if (aContext->CreatedDynamically()) {
-      return WalkFlag::Skip;
-    }
-
-    WindowContext* windowContext = aContext->GetCurrentWindowContext();
-    if (!windowContext) {
-      return WalkFlag::Skip;
-    }
-
-    WindowGlobalChild* windowChild = windowContext->GetWindowGlobalChild();
-    if (!windowChild) {
-      return WalkFlag::Next;
-    }
-
-    RefPtr<SessionStoreDataCollector> collector =
-        windowChild->GetSessionStoreDataCollector();
-    if (!collector) {
-      return WalkFlag::Next;
-    }
-
-    collector->Flush();
-    return WalkFlag::Next;
-  });
-
-  for (auto& child : nestedBrowserChilds) {
-    child->UpdateSessionStore();
-  }
-}
-
 std::tuple<bool, bool> BrowsingContext::CanFocusCheck(CallerType aCallerType) {
   nsFocusManager* fm = nsFocusManager::GetFocusManager();
   if (!fm) {
@@ -2635,6 +2598,20 @@ nsresult BrowsingContext::ResetGVAutoplayRequestStatus() {
   return txn.Commit(this);
 }
 
+void BrowsingContext::DidSet(FieldIndex<IDX_SessionStoreEpoch>,
+                             uint32_t aOldValue) {
+  if (!mCurrentWindowContext) {
+    return;
+  }
+  SessionStoreChild* sessionStoreChild =
+      SessionStoreChild::From(mCurrentWindowContext->GetWindowGlobalChild());
+  if (!sessionStoreChild) {
+    return;
+  }
+
+  sessionStoreChild->SetEpoch(GetSessionStoreEpoch());
+}
+
 void BrowsingContext::DidSet(FieldIndex<IDX_GVAudibleAutoplayRequestStatus>) {
   MOZ_ASSERT(IsTop(),
              "Should only set GVAudibleAutoplayRequestStatus in the top-level "
@@ -3407,6 +3384,17 @@ void BrowsingContext::AddDeprioritizedLoadRunner(nsIRunnable* aRunner) {
       EventQueuePriority::Idle);
 }
 
+bool BrowsingContext::IsDynamic() const {
+  const BrowsingContext* current = this;
+  do {
+    if (current->CreatedDynamically()) {
+      return true;
+    }
+  } while ((current = current->GetParent()));
+
+  return false;
+}
+
 bool BrowsingContext::GetOffsetPath(nsTArray<uint32_t>& aPath) const {
   for (const BrowsingContext* current = this; current && current->GetParent();
        current = current->GetParent()) {

docshell/base/BrowsingContext.h

@@ -784,6 +784,10 @@ class BrowsingContext : public nsILoadContext, public nsWrapperCache {
 
   bool CreatedDynamically() const { return mCreatedDynamically; }
 
+  // Returns true if this browsing context, or any ancestor to this browsing
+  // context was created dynamically. See also `CreatedDynamically`.
+  bool IsDynamic() const;
+
   int32_t ChildOffset() const { return mChildOffset; }
 
   bool GetOffsetPath(nsTArray<uint32_t>& aPath) const;
@@ -889,8 +893,6 @@ class BrowsingContext : public nsILoadContext, public nsWrapperCache {
     return GetPrefersColorSchemeOverride();
   }
 
-  void FlushSessionStore();
-
   bool IsInBFCache() const;
 
   bool AllowJavascript() const { return GetAllowJavascript(); }
@@ -1002,6 +1004,8 @@ class BrowsingContext : public nsILoadContext, public nsWrapperCache {
     return IsTop() && !aSource;
   }
 
+  void DidSet(FieldIndex<IDX_SessionStoreEpoch>, uint32_t aOldValue);
+
   using CanSetResult = syncedcontext::CanSetResult;
 
   // Ensure that opener is in the same BrowsingContextGroup.

docshell/base/CanonicalBrowsingContext.cpp

@@ -2367,7 +2367,7 @@ void CanonicalBrowsingContext::UpdateSessionStoreSessionStorage(
   using DataPromise = BackgroundSessionStorageManager::DataPromise;
   BackgroundSessionStorageManager::GetData(
       this, StaticPrefs::browser_sessionstore_dom_storage_limit(),
-      /* aCancelSessionStoreTiemr = */ true)
+      /* aClearSessionStoreTimer = */ true)
       ->Then(GetCurrentSerialEventTarget(), __func__,
              [self = RefPtr{this}, aDone, epoch = GetSessionStoreEpoch()](
                  const DataPromise::ResolveOrRejectValue& valueList) {

docshell/base/CanonicalBrowsingContext.h

@@ -55,6 +55,8 @@ class MediaController;
 struct LoadingSessionHistoryInfo;
 class SSCacheCopy;
 class WindowGlobalParent;
+class SessionStoreFormData;
+class SessionStoreScrollData;
 
 // CanonicalBrowsingContext is a BrowsingContext living in the parent
 // process, with whatever extra data that a BrowsingContext in the
@@ -524,6 +526,17 @@ class CanonicalBrowsingContext final : public BrowsingContext {
 
   RefPtr<FeaturePolicy> mContainerFeaturePolicy;
 
+  friend class BrowserSessionStore;
+  WeakPtr<SessionStoreFormData>& GetSessionStoreFormDataRef() {
+    return mFormdata;
+  }
+  WeakPtr<SessionStoreScrollData>& GetSessionStoreScrollDataRef() {
+    return mScroll;
+  }
+
+  WeakPtr<SessionStoreFormData> mFormdata;
+  WeakPtr<SessionStoreScrollData> mScroll;
+
   RefPtr<RestoreState> mRestoreState;
 
   // If this is a top level context, this is true if our browser ID is marked as

docshell/base/nsDocShell.cpp

@@ -78,7 +78,7 @@
 #include "mozilla/dom/SessionHistoryEntry.h"
 #include "mozilla/dom/SessionStorageManager.h"
 #include "mozilla/dom/SessionStoreChangeListener.h"
-#include "mozilla/dom/SessionStoreDataCollector.h"
+#include "mozilla/dom/SessionStoreChild.h"
 #include "mozilla/dom/SessionStoreUtils.h"
 #include "mozilla/dom/BrowserChild.h"
 #include "mozilla/dom/ToJSValue.h"
@@ -5816,7 +5816,12 @@ nsDocShell::OnStateChange(nsIWebProgress* aProgress, nsIRequest* aRequest,
 
       if constexpr (SessionStoreUtils::NATIVE_LISTENER) {
         if (IsForceReloadType(mLoadType)) {
-          SessionStoreUtils::ResetSessionStore(mBrowsingContext);
+          if (WindowContext* windowContext =
+                  mBrowsingContext->GetCurrentWindowContext()) {
+            SessionStoreChild::From(windowContext->GetWindowGlobalChild())
+                ->SendResetSessionStore(
+                    mBrowsingContext, mBrowsingContext->GetSessionStoreEpoch());
+          }
         }
       }
     }
@@ -6557,13 +6562,13 @@ nsresult nsDocShell::EndPageLoad(nsIWebProgress* aProgress,
     return NS_OK;
   }
   if constexpr (SessionStoreUtils::NATIVE_LISTENER) {
-    if (Document* document = GetDocument()) {
+    if (WindowContext* windowContext =
-      if (WindowGlobalChild* windowChild = document->GetWindowGlobalChild()) {
+            mBrowsingContext->GetCurrentWindowContext()) {
-        RefPtr<SessionStoreDataCollector> collector =
+      // TODO(farre): File bug: From a user perspective this would probably be
-            SessionStoreDataCollector::CollectSessionStoreData(windowChild);
+      // just fine to run off the change listener timer. Turns out that a flush
-        collector->RecordInputChange();
+      // is needed. Several tests depend on this behaviour. Could potentially be
-        collector->RecordScrollChange();
+      // an optimization for later. See Bug 1756995.
-      }
+      SessionStoreChangeListener::FlushAllSessionStoreData(windowContext);
     }
   }
 

dom/base/nsFrameLoader.cpp

@@ -86,15 +86,17 @@
 #include "mozilla/ScopeExit.h"
 #include "mozilla/StaticPrefs_fission.h"
 #include "mozilla/Unused.h"
+#include "mozilla/dom/BrowsingContext.h"
 #include "mozilla/dom/ChromeMessageSender.h"
 #include "mozilla/dom/Element.h"
 #include "mozilla/dom/FrameCrashedEvent.h"
 #include "mozilla/dom/FrameLoaderBinding.h"
+#include "mozilla/dom/InProcessChild.h"
 #include "mozilla/dom/MozFrameLoaderOwnerBinding.h"
 #include "mozilla/dom/PBrowser.h"
 #include "mozilla/dom/SessionHistoryEntry.h"
-#include "mozilla/dom/SessionStoreChangeListener.h"
+#include "mozilla/dom/SessionStoreChild.h"
-#include "mozilla/dom/SessionStoreListener.h"
+#include "mozilla/dom/SessionStoreParent.h"
 #include "mozilla/dom/SessionStoreUtils.h"
 #include "mozilla/dom/WindowGlobalParent.h"
 #include "mozilla/dom/XULFrameElement.h"
@@ -164,8 +166,7 @@ using PrintPreviewResolver = std::function<void(const PrintPreviewResultInfo&)>;
 
 NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(nsFrameLoader, mPendingBrowsingContext,
                                       mMessageManager, mChildMessageManager,
-                                      mRemoteBrowser,
+                                      mRemoteBrowser, mSessionStoreChild)
-                                      mSessionStoreChangeListener)
 NS_IMPL_CYCLE_COLLECTING_ADDREF(nsFrameLoader)
 NS_IMPL_CYCLE_COLLECTING_RELEASE(nsFrameLoader)
 
@@ -2041,14 +2042,9 @@ void nsFrameLoader::DestroyDocShell() {
     mChildMessageManager->FireUnloadEvent();
   }
 
-  if (mSessionStoreListener) {
+  if (mSessionStoreChild) {
-    mSessionStoreListener->RemoveListeners();
+    mSessionStoreChild->Stop();
-    mSessionStoreListener = nullptr;
+    mSessionStoreChild = nullptr;
-  }
-
-  if (mSessionStoreChangeListener) {
-    mSessionStoreChangeListener->Stop();
-    mSessionStoreChangeListener = nullptr;
   }
 
   // Destroy the docshell.
@@ -2141,22 +2137,22 @@ void nsFrameLoader::SetOwnerContent(Element* aContent) {
 #endif
   }
 
-  if (mSessionStoreListener && mOwnerContent) {
+  if (mSessionStoreChild && mOwnerContent) {
     // mOwnerContent will only be null when the frame loader is being destroyed,
     // so the session store listener will be destroyed along with it.
     // XXX(farre): This probably needs to update the cache. See bug 1698497.
-    mSessionStoreListener->SetOwnerContent(mOwnerContent);
+    mSessionStoreChild->SetOwnerContent(mOwnerContent);
   }
 
   if (RefPtr<BrowsingContext> browsingContext = GetExtantBrowsingContext()) {
     browsingContext->SetEmbedderElement(mOwnerContent);
   }
 
-  if (mSessionStoreChangeListener) {
+  if (mSessionStoreChild) {
     // UpdateEventTargets will requery its browser contexts for event
     // targets, so this call needs to happen after the call to
     // SetEmbedderElement above.
-    mSessionStoreChangeListener->UpdateEventTargets();
+    mSessionStoreChild->UpdateEventTargets();
   }
 
   AutoJSAPI jsapi;
@@ -3101,15 +3097,11 @@ nsresult nsFrameLoader::EnsureMessageManager() {
         GetDocShell(), mOwnerContent, mMessageManager);
     NS_ENSURE_TRUE(mChildMessageManager, NS_ERROR_UNEXPECTED);
 
-    // Set up a TabListener for sessionStore
+    // Set up session store
     if constexpr (SessionStoreUtils::NATIVE_LISTENER) {
-      if (XRE_IsParentProcess()) {
+      if (XRE_IsParentProcess() && mIsTopLevelContent) {
-        mSessionStoreListener = new TabListener(GetDocShell(), mOwnerContent);
+        mSessionStoreChild = SessionStoreChild::GetOrCreate(
-        rv = mSessionStoreListener->Init();
+            GetExtantBrowsingContext(), mOwnerContent);
-        NS_ENSURE_SUCCESS(rv, rv);
-
-        mSessionStoreChangeListener =
-            SessionStoreChangeListener::Create(GetExtantBrowsingContext());
       }
     }
   }
@@ -3237,6 +3229,21 @@ void nsFrameLoader::RequestUpdatePosition(ErrorResult& aRv) {
   }
 }
 
+SessionStoreParent* nsFrameLoader::GetSessionStoreParent() {
+  MOZ_DIAGNOSTIC_ASSERT(XRE_IsParentProcess());
+  if (mSessionStoreChild) {
+    return static_cast<SessionStoreParent*>(
+        InProcessChild::ParentActorFor(mSessionStoreChild));
+  }
+
+  if (BrowserParent* browserParent = GetBrowserParent()) {
+    return static_cast<SessionStoreParent*>(
+        SingleManagedOrNull(browserParent->ManagedPSessionStoreParent()));
+  }
+
+  return nullptr;
+}
+
 already_AddRefed<Promise> nsFrameLoader::RequestTabStateFlush(
     ErrorResult& aRv) {
   MOZ_DIAGNOSTIC_ASSERT(XRE_IsParentProcess());
@@ -3247,42 +3254,24 @@ already_AddRefed<Promise> nsFrameLoader::RequestTabStateFlush(
   }
 
   RefPtr<Promise> promise = Promise::Create(ownerDoc->GetOwnerGlobal(), aRv);
-
   if (aRv.Failed()) {
     return nullptr;
   }
 
-  RefPtr<BrowsingContext> context = GetExtantBrowsingContext();
+  BrowsingContext* browsingContext = GetExtantBrowsingContext();
-  if (!context) {
+  if (!browsingContext) {
     promise->MaybeResolveWithUndefined();
     return promise.forget();
   }
 
-  if (mSessionStoreListener) {
+  SessionStoreParent* sessionStoreParent = GetSessionStoreParent();
-    context->FlushSessionStore();
+  if (!sessionStoreParent) {
-    mSessionStoreListener->ForceFlushFromParent();
+    promise->MaybeResolveWithUndefined();
-    context->Canonical()->UpdateSessionStoreSessionStorage(
-        [promise]() { promise->MaybeResolveWithUndefined(); });
-
     return promise.forget();
   }
 
-  using FlushPromise = ContentParent::FlushTabStatePromise;
+  sessionStoreParent->FlushAllSessionStoreChildren(
-  nsTArray<RefPtr<FlushPromise>> flushPromises;
+      [promise]() { promise->MaybeResolveWithUndefined(); });
-  context->Group()->EachParent([&](ContentParent* aParent) {
-    if (aParent->CanSend()) {
-      flushPromises.AppendElement(aParent->SendFlushTabState(context));
-    }
-  });
-
-  RefPtr<FlushPromise::AllPromiseType> flushPromise =
-      FlushPromise::All(GetCurrentSerialEventTarget(), flushPromises);
-
-  context->Canonical()->UpdateSessionStoreSessionStorage([flushPromise,
-                                                          promise]() {
-    flushPromise->Then(GetCurrentSerialEventTarget(), __func__,
-                       [promise]() { promise->MaybeResolveWithUndefined(); });
-  });
 
   return promise.forget();
 }
@@ -3297,10 +3286,8 @@ void nsFrameLoader::RequestFinalTabStateFlush() {
   RefPtr<WindowGlobalParent> wgp = canonical->GetCurrentWindowGlobal();
   RefPtr<Element> embedder = context->GetEmbedderElement();
 
-  if (mSessionStoreListener) {
+  RefPtr<SessionStoreParent> sessionStoreParent = GetSessionStoreParent();
-    context->FlushSessionStore();
+  if (!sessionStoreParent) {
-    mSessionStoreListener->ForceFlushFromParent();
-
     canonical->ClearPermanentKey();
     if (wgp) {
       wgp->NotifySessionStoreUpdatesComplete(embedder);
@@ -3309,24 +3296,15 @@ void nsFrameLoader::RequestFinalTabStateFlush() {
     return;
   }
 
-  using FlushPromise = ContentParent::FlushTabStatePromise;
+  sessionStoreParent->FinalFlushAllSessionStoreChildren(
-  nsTArray<RefPtr<FlushPromise>> flushPromises;
+      [canonical, wgp, embedder]() {
-  context->Group()->EachParent([&](ContentParent* aParent) {
+        if (canonical) {
-    if (aParent->CanSend()) {
+          canonical->ClearPermanentKey();
-      flushPromises.AppendElement(aParent->SendFlushTabState(context));
+        }
-    }
+        if (wgp) {
-  });
+          wgp->NotifySessionStoreUpdatesComplete(embedder);
-
+        }
-  FlushPromise::All(GetCurrentSerialEventTarget(), flushPromises)
+      });
-      ->Then(GetCurrentSerialEventTarget(), __func__,
-             [canonical = RefPtr{canonical}, wgp, embedder]() {
-               if (canonical) {
-                 canonical->ClearPermanentKey();
-               }
-               if (wgp) {
-                 wgp->NotifySessionStoreUpdatesComplete(embedder);
-               }
-             });
 }
 
 void nsFrameLoader::RequestEpochUpdate(uint32_t aEpoch) {
@@ -3335,21 +3313,11 @@ void nsFrameLoader::RequestEpochUpdate(uint32_t aEpoch) {
     BrowsingContext* top = context->Top();
     Unused << top->SetSessionStoreEpoch(aEpoch);
   }
-
-  if (mSessionStoreListener) {
-    mSessionStoreListener->SetEpoch(aEpoch);
-    return;
-  }
-
-  // If remote browsing (e10s), handle this with the BrowserParent.
-  if (auto* browserParent = GetBrowserParent()) {
-    Unused << browserParent->SendUpdateEpoch(aEpoch);
-  }
 }
 
 void nsFrameLoader::RequestSHistoryUpdate() {
-  if (mSessionStoreListener) {
+  if (mSessionStoreChild) {
-    mSessionStoreListener->UpdateSHistoryChanges();
+    mSessionStoreChild->UpdateSHistoryChanges();
     return;
   }
 

dom/base/nsFrameLoader.h

@@ -63,7 +63,6 @@ class ChromeMessageSender;
 class ContentParent;
 class Document;
 class Element;
-class TabListener;
 class InProcessBrowserChildMessageManager;
 class MessageSender;
 class ProcessMessageManager;
@@ -73,7 +72,8 @@ class BrowserBridgeChild;
 class RemoteBrowser;
 struct RemotenessOptions;
 struct NavigationIsolationOptions;
-class SessionStoreChangeListener;
+class SessionStoreChild;
+class SessionStoreParent;
 
 namespace ipc {
 class StructuredCloneData;
@@ -411,6 +411,12 @@ class nsFrameLoader final : public nsStubMutationObserver,
 
   void FireErrorEvent();
 
+  mozilla::dom::SessionStoreChild* GetSessionStoreChild() {
+    return mSessionStoreChild;
+  }
+
+  mozilla::dom::SessionStoreParent* GetSessionStoreParent();
+
  private:
   nsFrameLoader(mozilla::dom::Element* aOwner,
                 mozilla::dom::BrowsingContext* aBrowsingContext, bool aIsRemote,
@@ -520,9 +526,10 @@ class nsFrameLoader final : public nsStubMutationObserver,
   // Holds the last known size of the frame.
   mozilla::ScreenIntSize mLazySize;
 
-  RefPtr<mozilla::dom::TabListener> mSessionStoreListener;
+  // Actor for collecting session store data from content children. This will be
-
+  // cleared and set to null eagerly when taking down the frameloader to break
-  RefPtr<mozilla::dom::SessionStoreChangeListener> mSessionStoreChangeListener;
+  // refcounted cycles early.
+  RefPtr<mozilla::dom::SessionStoreChild> mSessionStoreChild;
 
   nsCString mRemoteType;
 

dom/chrome-webidl/BrowserSessionStore.webidl

@@ -0,0 +1,47 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// object contains either a CollectedFileListValue or a CollectedNonMultipleSelectValue or Sequence<DOMString>
+typedef (DOMString or boolean or object) FormDataValue;
+
+[ChromeOnly, Exposed=Window]
+interface SessionStoreFormData {
+  [Cached, Pure]
+  readonly attribute ByteString? url;
+
+  [Cached, Pure]
+  readonly attribute record<DOMString, FormDataValue>? id;
+
+  [Cached, Pure]
+  readonly attribute record<DOMString, FormDataValue>? xpath;
+
+  [Cached, Pure]
+  readonly attribute DOMString? innerHTML;
+
+  [Cached, Frozen, Pure]
+  readonly attribute sequence<SessionStoreFormData?>? children;
+
+  object toJSON();
+};
+
+[ChromeOnly, Exposed=Window]
+interface SessionStoreScrollData {
+  [Cached, Pure]
+  readonly attribute ByteString? scroll;
+
+  [Cached, Pure]
+  readonly attribute sequence<SessionStoreScrollData?>? children;
+
+  object toJSON();
+};
+
+[GenerateConversionToJS]
+dictionary UpdateSessionStoreData {
+  // This is docshell caps, but on-disk format uses the disallow property name.
+  ByteString? disallow;
+  boolean isPrivate;
+  SessionStoreFormData? formdata;
+  SessionStoreScrollData? scroll;
+};

dom/chrome-webidl/SessionStoreUtils.webidl

@@ -167,28 +167,3 @@ dictionary InputElementData {
   sequence<DOMString> strVal;
   sequence<boolean> boolVal;
 };
-
-[GenerateConversionToJS]
-dictionary UpdateSessionStoreData {
-  ByteString docShellCaps;
-  boolean isPrivate;
-};
-
-[GenerateConversionToJS]
-dictionary SessionStoreWindowStateChange {
-  SessionStoreFormData formdata;
-  SessionStoreScroll scroll;
-  boolean hasChildren;
-  required sequence<unsigned long> path;
-};
-
-dictionary SessionStoreFormData {
-  ByteString url;
-  record<DOMString, CollectedFormDataValue> id;
-  record<DOMString, CollectedFormDataValue> xpath;
-  DOMString innerHTML;
-};
-
-dictionary SessionStoreScroll {
-  ByteString scroll;
-};

dom/chrome-webidl/moz.build

@@ -37,6 +37,7 @@ PREPROCESSED_WEBIDL_FILES = [
 ]
 
 WEBIDL_FILES = [
+    "BrowserSessionStore.webidl",
     "BrowsingContext.webidl",
     "ChannelWrapper.webidl",
     "ClonedErrorHolder.webidl",

dom/ipc/BrowserChild.cpp

@@ -69,10 +69,8 @@
 #include "mozilla/dom/PBrowser.h"
 #include "mozilla/dom/PaymentRequestChild.h"
 #include "mozilla/dom/PointerEventHandler.h"
-#include "mozilla/dom/SessionStoreChangeListener.h"
-#include "mozilla/dom/SessionStoreDataCollector.h"
-#include "mozilla/dom/SessionStoreListener.h"
 #include "mozilla/dom/SessionStoreUtils.h"
+#include "mozilla/dom/SessionStoreChild.h"
 #include "mozilla/dom/WindowGlobalChild.h"
 #include "mozilla/dom/WindowProxyHolder.h"
 #include "mozilla/gfx/CrossProcessPaint.h"
@@ -522,12 +520,7 @@ nsresult BrowserChild::Init(mozIDOMWindowProxy* aParent,
   mIPCOpen = true;
 
   if constexpr (SessionStoreUtils::NATIVE_LISTENER) {
-    mSessionStoreListener = new TabListener(docShell, nullptr);
+    mSessionStoreChild = SessionStoreChild::GetOrCreate(mBrowsingContext);
-    rv = mSessionStoreListener->Init();
-    NS_ENSURE_SUCCESS(rv, rv);
-
-    mSessionStoreChangeListener =
-        SessionStoreChangeListener::Create(mBrowsingContext);
   }
 
   // We've all set up, make sure our visibility state is consistent. This is
@@ -545,8 +538,7 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(BrowserChild)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mStatusFilter)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mWebNav)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mBrowsingContext)
-  NS_IMPL_CYCLE_COLLECTION_UNLINK(mSessionStoreListener)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mSessionStoreChild)
-  NS_IMPL_CYCLE_COLLECTION_UNLINK(mSessionStoreChangeListener)
   NS_IMPL_CYCLE_COLLECTION_UNLINK_WEAK_REFERENCE
 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
 
@@ -555,8 +547,7 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(BrowserChild)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mStatusFilter)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mWebNav)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mBrowsingContext)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mSessionStoreListener)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mSessionStoreChild)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mSessionStoreChangeListener)
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 
 NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(BrowserChild)
@@ -849,14 +840,9 @@ void BrowserChild::DestroyWindow() {
     mCoalescedTouchMoveEventFlusher = nullptr;
   }
 
-  if (mSessionStoreListener) {
+  if (mSessionStoreChild) {
-    mSessionStoreListener->RemoveListeners();
+    mSessionStoreChild->Stop();
-    mSessionStoreListener = nullptr;
+    mSessionStoreChild = nullptr;
-  }
-
-  if (mSessionStoreChangeListener) {
-    mSessionStoreChangeListener->Stop();
-    mSessionStoreChangeListener = nullptr;
   }
 
   // In case we don't have chance to process all entries, clean all data in
@@ -2060,16 +2046,9 @@ mozilla::ipc::IPCResult BrowserChild::RecvNativeSynthesisResponse(
   return IPC_OK();
 }
 
-mozilla::ipc::IPCResult BrowserChild::RecvUpdateEpoch(const uint32_t& aEpoch) {
-  if (mSessionStoreListener) {
-    mSessionStoreListener->SetEpoch(aEpoch);
-  }
-  return IPC_OK();
-}
-
 mozilla::ipc::IPCResult BrowserChild::RecvUpdateSHistory() {
-  if (mSessionStoreListener) {
+  if (mSessionStoreChild) {
-    mSessionStoreListener->UpdateSHistoryChanges();
+    mSessionStoreChild->UpdateSHistoryChanges();
   }
   return IPC_OK();
 }
@@ -3809,26 +3788,10 @@ nsresult BrowserChild::PrepareProgressListenerData(
   return PrepareRequestData(aRequest, aRequestData);
 }
 
-bool BrowserChild::UpdateSessionStore() {
+void BrowserChild::UpdateSessionStore() {
-  if (!mSessionStoreListener) {
+  if (mSessionStoreChild) {
-    return false;
+    mSessionStoreChild->UpdateSessionStore();
   }
-  RefPtr<ContentSessionStore> store = mSessionStoreListener->GetSessionStore();
-
-  Maybe<nsCString> docShellCaps;
-  if (store->IsDocCapChanged()) {
-    docShellCaps.emplace(store->GetDocShellCaps());
-  }
-
-  Maybe<bool> privatedMode;
-  if (store->IsPrivateChanged()) {
-    privatedMode.emplace(store->GetPrivateModeEnabled());
-  }
-
-  Unused << SendSessionStoreUpdate(docShellCaps, privatedMode,
-                                   store->GetAndClearSHistoryChanged(),
-                                   mSessionStoreListener->GetEpoch());
-  return true;
 }
 
 #ifdef XP_WIN

dom/ipc/BrowserChild.h

@@ -86,9 +86,7 @@ class TabGroup;
 class ClonedMessageData;
 class CoalescedMouseData;
 class CoalescedWheelData;
-class ContentSessionStore;
+class SessionStoreChild;
-class SessionStoreChangeListener;
-class TabListener;
 class RequestData;
 class WebProgressData;
 
@@ -396,8 +394,6 @@ class BrowserChild final : public nsMessageManagerScriptExecutor,
                                                 aApzResponse);
   }
 
-  mozilla::ipc::IPCResult RecvUpdateEpoch(const uint32_t& aEpoch);
-
   mozilla::ipc::IPCResult RecvUpdateSHistory();
 
   mozilla::ipc::IPCResult RecvNativeSynthesisResponse(
@@ -673,7 +669,11 @@ class BrowserChild final : public nsMessageManagerScriptExecutor,
     mCancelContentJSEpoch = aEpoch;
   }
 
-  bool UpdateSessionStore();
+  void UpdateSessionStore();
+
+  mozilla::dom::SessionStoreChild* GetSessionStoreChild() {
+    return mSessionStoreChild;
+  }
 
 #ifdef XP_WIN
   // Check if the window this BrowserChild is associated with supports
@@ -892,8 +892,7 @@ class BrowserChild final : public nsMessageManagerScriptExecutor,
   RefPtr<CoalescedTouchMoveFlusher> mCoalescedTouchMoveEventFlusher;
 
   RefPtr<layers::IAPZCTreeManager> mApzcTreeManager;
-  RefPtr<TabListener> mSessionStoreListener;
+  RefPtr<SessionStoreChild> mSessionStoreChild;
-  RefPtr<SessionStoreChangeListener> mSessionStoreChangeListener;
 
   // The most recently seen layer observer epoch in RecvSetDocShellIsActive.
   layers::LayersObserverEpoch mLayersObserverEpoch;

dom/ipc/BrowserParent.cpp

@@ -16,6 +16,7 @@
 #endif
 #include "mozilla/Components.h"
 #include "mozilla/dom/BrowserHost.h"
+#include "mozilla/dom/BrowserSessionStore.h"
 #include "mozilla/dom/BrowsingContextGroup.h"
 #include "mozilla/dom/CancelContentJSOptionsBinding.h"
 #include "mozilla/dom/ChromeMessageSender.h"
@@ -32,8 +33,7 @@
 #include "mozilla/dom/RemoteDragStartData.h"
 #include "mozilla/dom/RemoteWebProgressRequest.h"
 #include "mozilla/dom/SessionHistoryEntry.h"
-#include "mozilla/dom/SessionStoreUtils.h"
+#include "mozilla/dom/SessionStoreParent.h"
-#include "mozilla/dom/SessionStoreUtilsBinding.h"
 #include "mozilla/dom/UserActivation.h"
 #include "mozilla/EventStateManager.h"
 #include "mozilla/gfx/2D.h"
@@ -53,6 +53,7 @@
 #include "mozilla/Preferences.h"
 #include "mozilla/PresShell.h"
 #include "mozilla/ProcessHangMonitor.h"
+#include "mozilla/RefPtr.h"
 #include "mozilla/StaticPrefs_accessibility.h"
 #include "mozilla/StaticPrefs_dom.h"
 #include "mozilla/TextEventDispatcher.h"
@@ -128,7 +129,6 @@
 #include "mozilla/dom/CanonicalBrowsingContext.h"
 #include "mozilla/ProfilerLabels.h"
 #include "MMPrinter.h"
-#include "SessionStoreFunctions.h"
 #include "mozilla/dom/CrashReport.h"
 #include "nsISecureBrowserUI.h"
 #include "nsIXULRuntime.h"
@@ -1372,6 +1372,17 @@ IPCResult BrowserParent::RecvIndexedDBPermissionRequest(
   return IPC_OK();
 }
 
+already_AddRefed<PSessionStoreParent>
+BrowserParent::AllocPSessionStoreParent() {
+  RefPtr<BrowserSessionStore> sessionStore =
+      BrowserSessionStore::GetOrCreate(mBrowsingContext->Top());
+  if (!sessionStore) {
+    return nullptr;
+  }
+
+  return do_AddRef(new SessionStoreParent(mBrowsingContext, sessionStore));
+}
+
 IPCResult BrowserParent::RecvNewWindowGlobal(
     ManagedEndpoint<PWindowGlobalParent>&& aEndpoint,
     const WindowGlobalInit& aInit) {
@@ -3008,41 +3019,6 @@ BrowserParent::BrowsingContextForWebProgress(
   return browsingContext.forget();
 }
 
-mozilla::ipc::IPCResult BrowserParent::RecvSessionStoreUpdate(
-    const Maybe<nsCString>& aDocShellCaps, const Maybe<bool>& aPrivatedMode,
-    const bool aNeedCollectSHistory, const uint32_t& aEpoch) {
-  UpdateSessionStoreData data;
-  if (aDocShellCaps.isSome()) {
-    data.mDocShellCaps.Construct() = aDocShellCaps.value();
-  }
-  if (aPrivatedMode.isSome()) {
-    data.mIsPrivate.Construct() = aPrivatedMode.value();
-  }
-
-  nsCOMPtr<nsISessionStoreFunctions> funcs = do_ImportModule(
-      "resource://gre/modules/SessionStoreFunctions.jsm", fallible);
-  nsCOMPtr<nsIXPConnectWrappedJS> wrapped = do_QueryInterface(funcs);
-  NS_ENSURE_TRUE(wrapped, IPC_OK());
-
-  AutoJSAPI jsapi;
-  if (!jsapi.Init(wrapped->GetJSObjectGlobal())) {
-    return IPC_OK();
-  }
-
-  JS::Rooted<JS::Value> update(jsapi.cx());
-  if (!ToJSValue(jsapi.cx(), data, &update)) {
-    return IPC_OK();
-  }
-
-  JS::RootedValue key(jsapi.cx(),
-                      mBrowsingContext->Canonical()->Top()->PermanentKey());
-
-  Unused << funcs->UpdateSessionStore(mFrameElement, mBrowsingContext, key,
-                                      aEpoch, aNeedCollectSHistory, update);
-
-  return IPC_OK();
-}
-
 mozilla::ipc::IPCResult BrowserParent::RecvIntrinsicSizeOrRatioChanged(
     const Maybe<IntrinsicSize>& aIntrinsicSize,
     const Maybe<AspectRatio>& aIntrinsicRatio) {

dom/ipc/BrowserParent.h

@@ -317,10 +317,6 @@ class BrowserParent final : public PBrowserParent,
   already_AddRefed<CanonicalBrowsingContext> BrowsingContextForWebProgress(
       const WebProgressData& aWebProgressData);
 
-  mozilla::ipc::IPCResult RecvSessionStoreUpdate(
-      const Maybe<nsCString>& aDocShellCaps, const Maybe<bool>& aPrivatedMode,
-      const bool aNeedCollectSHistory, const uint32_t& aEpoch);
-
   mozilla::ipc::IPCResult RecvIntrinsicSizeOrRatioChanged(
       const Maybe<IntrinsicSize>& aIntrinsicSize,
       const Maybe<AspectRatio>& aIntrinsicRatio);
@@ -445,6 +441,8 @@ class BrowserParent final : public PBrowserParent,
       const IAccessibleHolder& aDocCOMProxy) override;
 #endif
 
+  already_AddRefed<PSessionStoreParent> AllocPSessionStoreParent();
+
   mozilla::ipc::IPCResult RecvNewWindowGlobal(
       ManagedEndpoint<PWindowGlobalParent>&& aEndpoint,
       const WindowGlobalInit& aInit);

dom/ipc/ContentChild.cpp

@@ -4524,25 +4524,6 @@ mozilla::ipc::IPCResult ContentChild::RecvInitNextGenLocalStorageEnabled(
   }
 }
 
-mozilla::ipc::IPCResult ContentChild::RecvFlushTabState(
-    const MaybeDiscarded<BrowsingContext>& aContext,
-    FlushTabStateResolver&& aResolver) {
-  if (aContext.IsNullOrDiscarded()) {
-    aResolver(false);
-    return IPC_OK();
-  }
-
-  if (auto* docShell = nsDocShell::Cast(aContext->GetDocShell())) {
-    docShell->CollectWireframe();
-  }
-
-  aContext->FlushSessionStore();
-
-  aResolver(true);
-
-  return IPC_OK();
-}
-
 mozilla::ipc::IPCResult ContentChild::RecvGoBack(
     const MaybeDiscarded<BrowsingContext>& aContext,
     const Maybe<int32_t>& aCancelContentJSEpoch, bool aRequireUserInteraction,

dom/ipc/ContentChild.h

@@ -812,10 +812,6 @@ class ContentChild final : public PContentChild,
       const MaybeDiscarded<BrowsingContext>& aStartingAt,
       DispatchBeforeUnloadToSubtreeResolver&& aResolver);
 
-  mozilla::ipc::IPCResult RecvFlushTabState(
-      const MaybeDiscarded<BrowsingContext>& aContext,
-      FlushTabStateResolver&& aResolver);
-
   mozilla::ipc::IPCResult RecvDecoderSupportedMimeTypes(
       nsTArray<nsCString>&& aSupportedTypes);
 

dom/ipc/PBrowser.ipdl

@@ -17,6 +17,7 @@ include protocol PParentToChildStream;
 include protocol PFileDescriptorSet;
 include protocol PRemoteLazyInputStream;
 include protocol PPaymentRequest;
+include protocol PSessionStore;
 include protocol PWindowGlobal;
 include protocol PBrowserBridge;
 include protocol PVsync;
@@ -190,6 +191,7 @@ struct PrintPreviewResultInfo
 
     manages PFilePicker;
     manages PPaymentRequest;
+    manages PSessionStore;
     manages PWindowGlobal;
     manages PBrowserBridge;
     manages PVsync;
@@ -575,9 +577,6 @@ parent:
 
     async NavigationFinished();
 
-    async SessionStoreUpdate(nsCString? aDocShellCaps, bool? aPrivatedMode,
-                             bool aNeedCollectSHistory, uint32_t aEpoch);
-
     async IntrinsicSizeOrRatioChanged(IntrinsicSize? aIntrinsicSize,
                                       AspectRatio? aIntrinsicRatio);
 
@@ -595,7 +594,6 @@ parent:
 
 child:
     async NativeSynthesisResponse(uint64_t aObserverId, nsCString aResponse);
-    async UpdateEpoch(uint32_t aEpoch);
     async UpdateSHistory();
     async CloneDocumentTreeIntoSelf(MaybeDiscardedBrowsingContext aBc, PrintData aPrintData) returns(bool aSuccess);
     async UpdateRemotePrintSettings(PrintData aPrintData);
@@ -1016,6 +1014,9 @@ parent:
     /** Fetches the visited status for an array of URIs (Android-only). */
     async QueryVisitedState(nsIURI[] aURIs);
 
+    /** Create a session store for a browser child. */
+    async PSessionStore();
+
     /**
      * Construct a new WindowGlobal for an existing global in the content process
      */

dom/ipc/PContent.ipdl

@@ -1027,9 +1027,6 @@ child:
   // Update the cached list of codec supported in the given process.
   async UpdateMediaCodecsSupported(RemoteDecodeIn aLocation, MediaCodecsSupported aSupported);
 
-  async FlushTabState(MaybeDiscardedBrowsingContext aBrowsingContext)
-      returns(bool aHadContext);
-
   // Send the list of the supported mimetypes in the given process. GeckoView-specific
   async DecoderSupportedMimeTypes(nsCString[] supportedTypes);
 

dom/ipc/PInProcess.ipdl

@@ -5,6 +5,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 include protocol PExtensions;
+include protocol PSessionStore;
 include protocol PWindowGlobal;
 
 include DOMTypes;
@@ -23,6 +24,7 @@ namespace dom {
 async protocol PInProcess
 {
   manages PExtensions;
+  manages PSessionStore;
   manages PWindowGlobal;
 };
 

dom/ipc/PWindowGlobal.ipdl

@@ -180,11 +180,6 @@ parent:
 
   async RequestRestoreTabContent();
 
-  async UpdateSessionStore(FormData? aFormData, nsPoint? aScrollPosition,
-                           uint32_t aEpoch);
-
-  async ResetSessionStore(uint32_t aEpoch);
-
   // Add the flags in aOnFlags to the current BFCache status and remove the
   // flags in aOffFlags from the current BFCache status. See the BFCacheStatus
   // enum for the valid flags.

dom/ipc/WindowGlobalChild.cpp

@@ -18,7 +18,6 @@
 #include "mozilla/dom/ContentParent.h"
 #include "mozilla/dom/SecurityPolicyViolationEvent.h"
 #include "mozilla/dom/SessionStoreRestoreData.h"
-#include "mozilla/dom/SessionStoreDataCollector.h"
 #include "mozilla/dom/WindowGlobalActorsBinding.h"
 #include "mozilla/dom/WindowContext.h"
 #include "mozilla/dom/InProcessChild.h"
@@ -327,11 +326,6 @@ void WindowGlobalChild::Destroy() {
   if (!browserChild || !browserChild->IsDestroyed()) {
     SendDestroy();
   }
-
-  if (mSessionStoreDataCollector) {
-    mSessionStoreDataCollector->Cancel();
-    mSessionStoreDataCollector = nullptr;
-  }
 }
 
 mozilla::ipc::IPCResult WindowGlobalChild::RecvMakeFrameLocal(
@@ -703,20 +697,9 @@ nsISupports* WindowGlobalChild::GetParentObject() {
   return xpc::NativeGlobal(xpc::PrivilegedJunkScope());
 }
 
-void WindowGlobalChild::SetSessionStoreDataCollector(
-    SessionStoreDataCollector* aCollector) {
-  mSessionStoreDataCollector = aCollector;
-}
-
-SessionStoreDataCollector* WindowGlobalChild::GetSessionStoreDataCollector()
-    const {
-  return mSessionStoreDataCollector;
-}
-
 NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_WEAK_PTR(WindowGlobalChild, mWindowGlobal,
                                                mContainerFeaturePolicy,
-                                               mWindowContext,
+                                               mWindowContext)
-                                               mSessionStoreDataCollector)
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(WindowGlobalChild)
   NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY

dom/ipc/WindowGlobalChild.h

@@ -28,7 +28,6 @@ class WindowGlobalParent;
 class JSWindowActorChild;
 class JSActorMessageMeta;
 class BrowserChild;
-class SessionStoreDataCollector;
 
 /**
  * Actor for a single nsGlobalWindowInner. This actor is used to communicate
@@ -133,9 +132,6 @@ class WindowGlobalChild final : public WindowGlobalActor,
     return mContainerFeaturePolicy;
   }
 
-  void SetSessionStoreDataCollector(SessionStoreDataCollector* aCollector);
-  SessionStoreDataCollector* GetSessionStoreDataCollector() const;
-
   void UnblockBFCacheFor(BFCacheStatus aStatus);
   void BlockBFCacheFor(BFCacheStatus aStatus);
 
@@ -205,7 +201,6 @@ class WindowGlobalChild final : public WindowGlobalActor,
   nsCOMPtr<nsIPrincipal> mDocumentPrincipal;
   RefPtr<dom::FeaturePolicy> mContainerFeaturePolicy;
   nsCOMPtr<nsIURI> mDocumentURI;
-  RefPtr<SessionStoreDataCollector> mSessionStoreDataCollector;
   int64_t mBeforeUnloadListeners = 0;
 };
 

dom/ipc/WindowGlobalParent.cpp

@@ -26,9 +26,6 @@
 #include "mozilla/dom/ChromeUtils.h"
 #include "mozilla/dom/ipc/IdType.h"
 #include "mozilla/dom/ipc/StructuredCloneData.h"
-#include "mozilla/dom/sessionstore/SessionStoreTypes.h"
-#include "mozilla/dom/SessionStoreUtils.h"
-#include "mozilla/dom/SessionStoreUtilsBinding.h"
 #include "mozilla/Components.h"
 #include "mozilla/ScopeExit.h"
 #include "mozilla/ServoCSSParser.h"
@@ -535,16 +532,6 @@ const nsACString& WindowGlobalParent::GetRemoteType() {
   return NOT_REMOTE_TYPE;
 }
 
-static nsCString PointToString(const nsPoint& aPoint) {
-  int scrollX = nsPresContext::AppUnitsToIntCSSPixels(aPoint.x);
-  int scrollY = nsPresContext::AppUnitsToIntCSSPixels(aPoint.y);
-  if ((scrollX != 0) || (scrollY != 0)) {
-    return nsPrintfCString("%d,%d", scrollX, scrollY);
-  }
-
-  return ""_ns;
-}
-
 void WindowGlobalParent::NotifyContentBlockingEvent(
     uint32_t aEvent, nsIRequest* aRequest, bool aBlocked,
     const nsACString& aTrackingOrigin,
@@ -1166,44 +1153,6 @@ void WindowGlobalParent::FinishAccumulatingPageUseCounters() {
   mPageUseCounters = nullptr;
 }
 
-static void GetFormData(JSContext* aCx, const sessionstore::FormData& aFormData,
-                        nsIURI* aDocumentURI, SessionStoreFormData& aUpdate) {
-  if (!aFormData.hasData()) {
-    return;
-  }
-
-  bool parseSessionData = false;
-  if (aDocumentURI) {
-    nsCString& url = aUpdate.mUrl.Construct();
-    aDocumentURI->GetSpecIgnoringRef(url);
-    // We want to avoid saving data for about:sessionrestore as a string.
-    // Since it's stored in the form as stringified JSON, stringifying
-    // further causes an explosion of escape characters. cf. bug 467409
-    parseSessionData =
-        url == "about:sessionrestore"_ns || url == "about:welcomeback"_ns;
-  }
-
-  if (!aFormData.innerHTML().IsEmpty()) {
-    aUpdate.mInnerHTML.Construct(aFormData.innerHTML());
-  }
-
-  if (!aFormData.id().IsEmpty()) {
-    auto& id = aUpdate.mId.Construct();
-    if (NS_FAILED(SessionStoreUtils::ConstructFormDataValues(
-            aCx, aFormData.id(), id.Entries(), parseSessionData))) {
-      return;
-    }
-  }
-
-  if (!aFormData.xpath().IsEmpty()) {
-    auto& xpath = aUpdate.mXpath.Construct();
-    if (NS_FAILED(SessionStoreUtils::ConstructFormDataValues(
-            aCx, aFormData.xpath(), xpath.Entries()))) {
-      return;
-    }
-  }
-}
-
 Element* WindowGlobalParent::GetRootOwnerElement() {
   WindowGlobalParent* top = TopWindowContext();
   if (!top) {
@@ -1221,104 +1170,6 @@ Element* WindowGlobalParent::GetRootOwnerElement() {
   return nullptr;
 }
 
-nsresult WindowGlobalParent::WriteFormDataAndScrollToSessionStore(
-    const Maybe<FormData>& aFormData, const Maybe<nsPoint>& aScrollPosition,
-    uint32_t aEpoch) {
-  if (!aFormData && !aScrollPosition) {
-    return NS_OK;
-  }
-
-  RefPtr<CanonicalBrowsingContext> context = BrowsingContext();
-  if (!context) {
-    return NS_OK;
-  }
-
-  nsCOMPtr<nsISessionStoreFunctions> funcs = do_ImportModule(
-      "resource://gre/modules/SessionStoreFunctions.jsm", fallible);
-  if (!funcs) {
-    return NS_ERROR_FAILURE;
-  }
-
-  nsCOMPtr<nsIXPConnectWrappedJS> wrapped = do_QueryInterface(funcs);
-  AutoJSAPI jsapi;
-  if (!jsapi.Init(wrapped->GetJSObjectGlobal())) {
-    return NS_ERROR_FAILURE;
-  }
-
-  RootedDictionary<SessionStoreWindowStateChange> windowState(jsapi.cx());
-
-  if (aFormData) {
-    GetFormData(jsapi.cx(), *aFormData, mDocumentURI,
-                windowState.mFormdata.Construct());
-  }
-
-  if (aScrollPosition) {
-    auto& update = windowState.mScroll.Construct();
-    if (*aScrollPosition != nsPoint(0, 0)) {
-      update.mScroll.Construct() = PointToString(*aScrollPosition);
-    }
-  }
-
-  nsTArray<uint32_t> path;
-  if (!context->GetOffsetPath(path)) {
-    return NS_OK;
-  }
-
-  windowState.mPath = std::move(path);
-  windowState.mHasChildren.Construct() = !context->Children().IsEmpty();
-
-  JS::RootedValue update(jsapi.cx());
-  if (!ToJSValue(jsapi.cx(), windowState, &update)) {
-    return NS_ERROR_FAILURE;
-  }
-
-  JS::RootedValue key(jsapi.cx(), context->Top()->PermanentKey());
-
-  return funcs->UpdateSessionStoreForWindow(GetRootOwnerElement(), context, key,
-                                            aEpoch, update);
-}
-
-nsresult WindowGlobalParent::ResetSessionStore(uint32_t aEpoch) {
-  RefPtr<CanonicalBrowsingContext> context = BrowsingContext();
-  if (!context) {
-    return NS_OK;
-  }
-
-  nsCOMPtr<nsISessionStoreFunctions> funcs = do_ImportModule(
-      "resource://gre/modules/SessionStoreFunctions.jsm", fallible);
-  if (!funcs) {
-    return NS_ERROR_FAILURE;
-  }
-
-  nsCOMPtr<nsIXPConnectWrappedJS> wrapped = do_QueryInterface(funcs);
-  AutoJSAPI jsapi;
-  if (!jsapi.Init(wrapped->GetJSObjectGlobal())) {
-    return NS_ERROR_FAILURE;
-  }
-
-  RootedDictionary<SessionStoreWindowStateChange> windowState(jsapi.cx());
-
-  nsTArray<uint32_t> path;
-  if (!context->GetOffsetPath(path)) {
-    return NS_OK;
-  }
-
-  windowState.mPath = std::move(path);
-  windowState.mHasChildren.Construct() = false;
-  windowState.mFormdata.Construct();
-  windowState.mScroll.Construct();
-
-  JS::RootedValue update(jsapi.cx());
-  if (!ToJSValue(jsapi.cx(), windowState, &update)) {
-    return NS_ERROR_FAILURE;
-  }
-
-  JS::RootedValue key(jsapi.cx(), context->Top()->PermanentKey());
-
-  return funcs->UpdateSessionStoreForWindow(GetRootOwnerElement(), context, key,
-                                            aEpoch, update);
-}
-
 void WindowGlobalParent::NotifySessionStoreUpdatesComplete(Element* aEmbedder) {
   if (!aEmbedder) {
     aEmbedder = GetRootOwnerElement();
@@ -1331,27 +1182,6 @@ void WindowGlobalParent::NotifySessionStoreUpdatesComplete(Element* aEmbedder) {
   }
 }
 
-mozilla::ipc::IPCResult WindowGlobalParent::RecvUpdateSessionStore(
-    const Maybe<FormData>& aFormData, const Maybe<nsPoint>& aScrollPosition,
-    uint32_t aEpoch) {
-  if (NS_FAILED(WriteFormDataAndScrollToSessionStore(aFormData, aScrollPosition,
-                                                     aEpoch))) {
-    MOZ_LOG(BrowsingContext::GetLog(), LogLevel::Debug,
-            ("ParentIPC: Failed to update session store entry."));
-  }
-
-  return IPC_OK();
-}
-
-mozilla::ipc::IPCResult WindowGlobalParent::RecvResetSessionStore(
-    uint32_t aEpoch) {
-  if (NS_FAILED(ResetSessionStore(aEpoch))) {
-    MOZ_LOG(BrowsingContext::GetLog(), LogLevel::Debug,
-            ("ParentIPC: Failed to reset session store entry."));
-  }
-  return IPC_OK();
-}
-
 mozilla::ipc::IPCResult WindowGlobalParent::RecvRequestRestoreTabContent() {
   CanonicalBrowsingContext* bc = BrowsingContext();
   if (bc && bc->AncestorsAreCurrent()) {

dom/ipc/WindowGlobalParent.h

@@ -80,7 +80,7 @@ class WindowGlobalParent final : public WindowContext,
   WindowGlobalParent* TopWindowContext() {
     return static_cast<WindowGlobalParent*>(WindowContext::TopWindowContext());
   }
-  CanonicalBrowsingContext* GetBrowsingContext() {
+  CanonicalBrowsingContext* GetBrowsingContext() const {
     return CanonicalBrowsingContext::Cast(WindowContext::GetBrowsingContext());
   }
 
@@ -214,10 +214,6 @@ class WindowGlobalParent final : public WindowContext,
 
   const nsACString& GetRemoteType() override;
 
-  nsresult WriteFormDataAndScrollToSessionStore(
-      const Maybe<FormData>& aFormData, const Maybe<nsPoint>& aScrollPosition,
-      uint32_t aEpoch);
-
   void NotifySessionStoreUpdatesComplete(Element* aEmbedder);
 
   Maybe<uint64_t> GetSingleChannelId() { return mSingleChannelId; }
@@ -288,12 +284,6 @@ class WindowGlobalParent final : public WindowContext,
 
   mozilla::ipc::IPCResult RecvRequestRestoreTabContent();
 
-  mozilla::ipc::IPCResult RecvUpdateSessionStore(
-      const Maybe<FormData>& aFormData, const Maybe<nsPoint>& aScrollPosition,
-      uint32_t aEpoch);
-
-  mozilla::ipc::IPCResult RecvResetSessionStore(uint32_t aEpoch);
-
   mozilla::ipc::IPCResult RecvUpdateBFCacheStatus(const uint32_t& aOnFlags,
                                                   const uint32_t& aOffFlags);
 
@@ -320,8 +310,6 @@ class WindowGlobalParent final : public WindowContext,
   bool ShouldTrackSiteOriginTelemetry();
   void FinishAccumulatingPageUseCounters();
 
-  nsresult ResetSessionStore(uint32_t aEpoch);
-
   // Returns failure if the new storage principal cannot be validated
   // against the current document principle.
   nsresult SetDocumentStoragePrincipal(

toolkit/components/sessionstore/BrowserSessionStore.cpp

@@ -0,0 +1,293 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/dom/BrowserSessionStore.h"
+#include <algorithm>
+#include <cstdint>
+#include <functional>
+
+#include "mozilla/AlreadyAddRefed.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/IntegerRange.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/StaticPtr.h"
+
+#include "mozilla/dom/BrowserSessionStoreBinding.h"
+#include "mozilla/dom/CanonicalBrowsingContext.h"
+#include "mozilla/dom/SessionStoreFormData.h"
+#include "mozilla/dom/SessionStoreScrollData.h"
+#include "mozilla/dom/WindowGlobalParent.h"
+
+#include "nsTHashMap.h"
+#include "nsHashtablesFwd.h"
+
+#include "js/RootingAPI.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
+
+static StaticAutoPtr<nsTHashMap<nsUint64HashKey, BrowserSessionStore*>>
+    sSessionStore;
+
+NS_IMPL_CYCLE_COLLECTION(BrowserSessionStore, mBrowsingContext, mFormData,
+                         mScrollData)
+
+NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(BrowserSessionStore, AddRef)
+NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(BrowserSessionStore, Release)
+
+/* static */
+already_AddRefed<BrowserSessionStore> BrowserSessionStore::GetOrCreate(
+    CanonicalBrowsingContext* aBrowsingContext) {
+  if (!aBrowsingContext->IsTop()) {
+    return nullptr;
+  }
+
+  if (!sSessionStore) {
+    sSessionStore = new nsTHashMap<nsUint64HashKey, BrowserSessionStore*>();
+    ClearOnShutdown(&sSessionStore);
+  }
+
+  return do_AddRef(sSessionStore->LookupOrInsertWith(
+      aBrowsingContext->Id(),
+      [&] { return new BrowserSessionStore(aBrowsingContext); }));
+}
+
+BrowserSessionStore::BrowserSessionStore(
+    CanonicalBrowsingContext* aBrowsingContext)
+    : mBrowsingContext(aBrowsingContext) {}
+
+SessionStoreFormData* BrowserSessionStore::GetFormdata() { return mFormData; }
+
+SessionStoreScrollData* BrowserSessionStore::GetScroll() { return mScrollData; }
+
+static bool ShouldUpdateSessionStore(CanonicalBrowsingContext* aBrowsingContext,
+                                     uint32_t aEpoch) {
+  if (!aBrowsingContext) {
+    return false;
+  }
+
+  if (aBrowsingContext->Top()->GetSessionStoreEpoch() != aEpoch) {
+    return false;
+  }
+
+  if (aBrowsingContext->IsReplaced()) {
+    return false;
+  }
+
+  if (aBrowsingContext->IsDynamic()) {
+    return false;
+  }
+
+  return true;
+}
+
+// With GetOrCreate we can create either of the weak fields:
+//   WeakPtr<SessionStoreFormData> mFormdata;
+//   WeakPtr<SessionStoreScrollData> mScroll;
+// in CanonicalBrowsingContext. If one already exists, then we return that.
+template <typename T, WeakPtr<T>& (CanonicalBrowsingContext::*GetWeakRef)()>
+static already_AddRefed<T> GetOrCreateEntry(
+    CanonicalBrowsingContext* aBrowsingContext) {
+  typename T::LocationType& location = (aBrowsingContext->*GetWeakRef)();
+  RefPtr<T> entry = location.get();
+  if (!entry) {
+    entry = MakeRefPtr<T>();
+    location = entry;
+  }
+
+  return entry.forget();
+}
+
+// With InsertEntry we can insert an entry in the session store data tree in
+// either of the weak fields:
+//   WeakPtr<SessionStoreFormData> mFormdata;
+//   WeakPtr<SessionStoreScrollData> mScroll;
+// in CanonicalBrowsingContext. If an entry is inserted where there is no parent
+// entry, a spine of entries will be created until one is found, or we reach the
+// top browsing context.
+template <typename T>
+void InsertEntry(BrowsingContext* aBrowsingContext, T* aParent, T* aUpdate) {
+  int32_t offset = aBrowsingContext->ChildOffset();
+  if (offset < 0) {
+    return;
+  }
+
+  aParent->ClearCachedChildren();
+
+  auto& children = aParent->Children();
+
+  children.EnsureLengthAtLeast(offset + 1);
+  if (children[offset] && !aBrowsingContext->Children().IsEmpty()) {
+    children[offset]->ClearCachedChildren();
+    aUpdate->ClearCachedChildren();
+  }
+
+  children[offset] = aUpdate;
+}
+
+// With RemoveEntry we can remove an entry in the session store data tree in
+// either of the weak fields:
+//   WeakPtr<SessionStoreFormData> mFormdata;
+//   WeakPtr<SessionStoreScrollData> mScroll;
+// in CanonicalBrowsingContext. If an entry is removed, where its parent doesn't
+// contain data, we'll remove the parent and repeat until we either find an
+// entry with data or reach the top browsing context.
+template <typename T>
+void RemoveEntry(BrowsingContext* aBrowsingContext, T* aParent) {
+  int32_t offset = aBrowsingContext->ChildOffset();
+  if (offset < 0) {
+    return;
+  }
+
+  if (!aParent) {
+    return;
+  }
+
+  aParent->ClearCachedChildren();
+
+  auto& children = aParent->Children();
+  size_t length = children.Length();
+  if (children.Length() <= static_cast<size_t>(offset)) {
+    // The children array doesn't extend to offset.
+    return;
+  }
+
+  if (static_cast<size_t>(offset) < length - 1) {
+    // offset is before the last item in the children array.
+    children[offset] = nullptr;
+    return;
+  }
+
+  // offset is the last item, find the first non-null item before it
+  // and remove anything after that item.
+  while (offset > 0 && !children[offset - 1]) {
+    --offset;
+  }
+
+  children.TruncateLength(offset);
+}
+
+// With UpdateSessionStoreField we can update an entry in the session store
+// data tree in either of the weak fields:
+//   WeakPtr<SessionStoreFormData> mFormdata;
+//   WeakPtr<SessionStoreScrollData> mScroll;
+// in CanonicalBrowsingContext. UpdateSessionStoreField uses the above
+// functions, `GetOrCreateEntry`, `InsertEntry` and `RemoveEntry` to operate on
+// the weak fields. We return the top-level entry attached to the top browsing
+// context through `aEntry`. If the entire browsing context tree contains no
+// session store data this will be set to nullptr.
+template <typename T, WeakPtr<T>& (CanonicalBrowsingContext::*GetWeakRef)()>
+void UpdateSessionStoreField(CanonicalBrowsingContext* aBrowsingContext,
+                             const typename T::CollectedType& aUpdate,
+                             T** aEntry) {
+  RefPtr<T> currentEntry;
+
+  if (T::HasData(aUpdate)) {
+    currentEntry = GetOrCreateEntry<T, GetWeakRef>(aBrowsingContext);
+    currentEntry->Update(aUpdate);
+
+    CanonicalBrowsingContext* currentBrowsingContext = aBrowsingContext;
+    while (CanonicalBrowsingContext* parent =
+               currentBrowsingContext->GetParent()) {
+      WeakPtr<T>& parentEntry = (parent->*GetWeakRef)();
+      if (parentEntry) {
+        InsertEntry(aBrowsingContext, parentEntry.get(), currentEntry.get());
+        break;
+      }
+
+      RefPtr<T> entry = GetOrCreateEntry<T, GetWeakRef>(parent);
+      InsertEntry(currentBrowsingContext, entry.get(), currentEntry.get());
+
+      currentEntry = entry;
+      currentBrowsingContext = parent;
+    }
+
+    currentEntry = (aBrowsingContext->Top()->*GetWeakRef)().get();
+  } else if ((currentEntry = (aBrowsingContext->*GetWeakRef)())) {
+    currentEntry->Update(aUpdate);
+
+    CanonicalBrowsingContext* currentBrowsingContext = aBrowsingContext;
+    while (CanonicalBrowsingContext* parent =
+               currentBrowsingContext->GetParent()) {
+      if (!currentEntry || !currentEntry->IsEmpty()) {
+        break;
+      }
+
+      T* parentEntry = (parent->*GetWeakRef)().get();
+      RemoveEntry(currentBrowsingContext, parentEntry);
+
+      currentEntry = parentEntry;
+      currentBrowsingContext = parent;
+    }
+
+    if (currentEntry && currentEntry->IsEmpty()) {
+      currentEntry = nullptr;
+    } else {
+      currentEntry = (aBrowsingContext->Top()->*GetWeakRef)().get();
+    }
+  }
+
+  *aEntry = currentEntry.forget().take();
+}
+
+void BrowserSessionStore::UpdateSessionStore(
+    CanonicalBrowsingContext* aBrowsingContext,
+    const Maybe<sessionstore::FormData>& aFormData,
+    const Maybe<nsPoint>& aScrollPosition, uint32_t aEpoch) {
+  if (!aFormData && !aScrollPosition) {
+    return;
+  }
+
+  if (!ShouldUpdateSessionStore(aBrowsingContext, aEpoch)) {
+    return;
+  }
+
+  if (aFormData) {
+    UpdateSessionStoreField<
+        SessionStoreFormData,
+        &CanonicalBrowsingContext::GetSessionStoreFormDataRef>(
+        aBrowsingContext, *aFormData, getter_AddRefs(mFormData));
+  }
+
+  if (aScrollPosition) {
+    UpdateSessionStoreField<
+        SessionStoreScrollData,
+        &CanonicalBrowsingContext::GetSessionStoreScrollDataRef>(
+        aBrowsingContext, *aScrollPosition, getter_AddRefs(mScrollData));
+  }
+}
+
+void BrowserSessionStore::RemoveSessionStore(
+    CanonicalBrowsingContext* aBrowsingContext) {
+  if (!aBrowsingContext) {
+    return;
+  }
+
+  CanonicalBrowsingContext* parentContext = aBrowsingContext->GetParent();
+
+  if (parentContext) {
+    RemoveEntry(aBrowsingContext,
+                parentContext->GetSessionStoreFormDataRef().get());
+
+    RemoveEntry(aBrowsingContext,
+                parentContext->GetSessionStoreScrollDataRef().get());
+
+    return;
+  }
+
+  if (aBrowsingContext->IsTop()) {
+    mFormData = nullptr;
+    mScrollData = nullptr;
+  }
+}
+
+BrowserSessionStore::~BrowserSessionStore() {
+  if (sSessionStore) {
+    sSessionStore->Remove(mBrowsingContext->Id());
+  }
+}

toolkit/components/sessionstore/BrowserSessionStore.h

@@ -0,0 +1,57 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_dom_SessionStore_h
+#define mozilla_dom_SessionStore_h
+
+#include "nsWrapperCache.h"
+
+#include "mozilla/Maybe.h"
+
+struct nsPoint;
+
+namespace mozilla::dom {
+
+class CanonicalBrowsingContext;
+class GlobalObject;
+class SessionStoreFormData;
+class SessionStoreScrollData;
+class WindowGlobalParent;
+
+namespace sessionstore {
+class FormData;
+}
+
+class BrowserSessionStore final {
+ public:
+  NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(BrowserSessionStore)
+  NS_DECL_CYCLE_COLLECTION_NATIVE_CLASS(BrowserSessionStore)
+
+  static already_AddRefed<BrowserSessionStore> GetOrCreate(
+      CanonicalBrowsingContext* aBrowsingContext);
+
+  SessionStoreFormData* GetFormdata();
+  SessionStoreScrollData* GetScroll();
+
+  void UpdateSessionStore(CanonicalBrowsingContext* aBrowsingContext,
+                          const Maybe<sessionstore::FormData>& aFormData,
+                          const Maybe<nsPoint>& aScrollPosition,
+                          uint32_t aEpoch);
+
+  void RemoveSessionStore(CanonicalBrowsingContext* aBrowsingContext);
+
+ private:
+  explicit BrowserSessionStore(CanonicalBrowsingContext* aBrowsingContext);
+  virtual ~BrowserSessionStore();
+
+  RefPtr<CanonicalBrowsingContext> mBrowsingContext;
+  RefPtr<SessionStoreFormData> mFormData;
+  RefPtr<SessionStoreScrollData> mScrollData;
+};
+
+}  // namespace mozilla::dom
+
+#endif  // mozilla_dom_SessionStore_h

toolkit/components/sessionstore/PSessionStore.ipdl

@@ -0,0 +1,60 @@
+/* -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil; tab-width: 8 -*- */
+/* vim: set sw=2 ts=8 et tw=80 ft=cpp : */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+include protocol PBrowser;
+include protocol PInProcess;
+include SessionStoreTypes;
+
+using mozilla::dom::MaybeDiscardedBrowsingContext from "mozilla/dom/BrowsingContext.h";
+
+namespace mozilla {
+namespace dom {
+
+/**
+ * The PSessionStore actor handles collection of session store data from content
+ * type documents. It can be used both in a content process and in the parent
+ * process. In particular it solves the problem of handling incremental updates
+ * to the session store, since we're collecting from potentially several content
+ * processes.
+ */
+async protocol PSessionStore
+{
+  manager PBrowser or PInProcess;
+
+parent:
+  /**
+   * Sends data to be stored and instructions to the session store to
+   * potentially collect data in the parent. This is data that is not
+   * collected incrementally.
+   */
+  async SessionStoreUpdate(
+    nsCString? aDocShellCaps, bool? aPrivateMode, bool aNeedCollectSHistory,
+    uint32_t aEpoch);
+
+  /**
+   * Sends data to be stored to the session store. The collected data
+   * is all the collected changed data from all the in-process documents
+   * in the process in which the SessionStoreChild actor lives.
+   */
+  async IncrementalSessionStoreUpdate(
+    MaybeDiscardedBrowsingContext aBrowsingContext, FormData? aFormData,
+    nsPoint? aScrollPosition, uint32_t aEpoch);
+
+  /**
+   * Drop all the collected data associated with the provided browsing
+   * context.
+   */
+  async ResetSessionStore(
+    MaybeDiscardedBrowsingContext aBrowsingContext, uint32_t aEpoch);
+
+child:
+  async FlushTabState() returns(bool aHadContext);
+
+  async __delete__();
+};
+
+} // namespace dom
+} // namespace mozilla

toolkit/components/sessionstore/SessionStoreChangeListener.cpp

@@ -10,13 +10,23 @@
 #include "mozilla/dom/Element.h"
 #include "mozilla/dom/Event.h"
 #include "mozilla/dom/EventTarget.h"
-#include "mozilla/dom/SessionStoreDataCollector.h"
+#include "mozilla/dom/SessionStoreChild.h"
 #include "mozilla/dom/SessionStoreUtils.h"
 #include "mozilla/dom/WindowGlobalChild.h"
 #include "mozilla/Preferences.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/StaticPrefs_browser.h"
 
+#include "nsBaseHashtable.h"
 #include "nsDocShell.h"
+#include "nsGenericHTMLElement.h"
+#include "nsIXULRuntime.h"
 #include "nsPIDOMWindow.h"
+#include "nsTHashMap.h"
+#include "nsTHashtable.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
 
 namespace {
 constexpr auto kInput = u"input"_ns;
@@ -28,13 +38,28 @@ static constexpr char kInterval[] = "browser.sessionstore.interval";
 static const char* kObservedPrefs[] = {kNoAutoUpdates, kInterval, nullptr};
 }  // namespace
 
-namespace mozilla::dom {
+inline void ImplCycleCollectionUnlink(
+    SessionStoreChangeListener::SessionStoreChangeTable& aField) {
+  aField.Clear();
+}
+
+inline void ImplCycleCollectionTraverse(
+    nsCycleCollectionTraversalCallback& aCallback,
+    const SessionStoreChangeListener::SessionStoreChangeTable& aField,
+    const char* aName, uint32_t aFlags = 0) {
+  for (auto iter = aField.ConstIter(); !iter.Done(); iter.Next()) {
+    CycleCollectionNoteChild(aCallback, iter.Key(), aName, aFlags);
+  }
+}
 
 NS_IMPL_CYCLE_COLLECTION(SessionStoreChangeListener, mBrowsingContext,
-                         mCurrentEventTarget)
+                         mCurrentEventTarget, mSessionStoreChild,
+                         mSessionStoreChanges)
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(SessionStoreChangeListener)
+  NS_INTERFACE_MAP_ENTRY(nsINamed)
   NS_INTERFACE_MAP_ENTRY(nsIObserver)
+  NS_INTERFACE_MAP_ENTRY(nsITimerCallback)
   NS_INTERFACE_MAP_ENTRY(nsIDOMEventListener)
   NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIObserver)
 NS_INTERFACE_MAP_END
@@ -42,10 +67,22 @@ NS_INTERFACE_MAP_END
 NS_IMPL_CYCLE_COLLECTING_ADDREF(SessionStoreChangeListener)
 NS_IMPL_CYCLE_COLLECTING_RELEASE(SessionStoreChangeListener)
 
+NS_IMETHODIMP
+SessionStoreChangeListener::GetName(nsACString& aName) {
+  aName.AssignLiteral("SessionStoreChangeListener");
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+SessionStoreChangeListener::Notify(nsITimer* aTimer) {
+  FlushSessionStore();
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 SessionStoreChangeListener::Observe(nsISupports* aSubject, const char* aTopic,
                                     const char16_t* aData) {
-  Flush();
+  FlushSessionStore();
   return NS_OK;
 }
 
@@ -62,45 +99,33 @@ SessionStoreChangeListener::HandleEvent(dom::Event* aEvent) {
     return NS_OK;
   }
 
-  WindowGlobalChild* windowChild = inner->GetWindowGlobalChild();
+  WindowContext* windowContext = inner->GetWindowContext();
-  if (!windowChild) {
+  if (!windowContext) {
     return NS_OK;
   }
 
-  RefPtr<BrowsingContext> browsingContext = windowChild->BrowsingContext();
+  RefPtr<BrowsingContext> browsingContext = windowContext->GetBrowsingContext();
   if (!browsingContext) {
     return NS_OK;
   }
 
-  bool dynamic = false;
+  if (browsingContext->IsDynamic()) {
-  BrowsingContext* current = browsingContext;
-  while (current) {
-    if ((dynamic = current->CreatedDynamically())) {
-      break;
-    }
-    current = current->GetParent();
-  }
-
-  if (dynamic) {
     return NS_OK;
   }
 
   nsAutoString eventType;
   aEvent->GetType(eventType);
 
-  RefPtr<SessionStoreDataCollector> collector =
+  Change change = Change::None;
-      SessionStoreDataCollector::CollectSessionStoreData(windowChild);
-
-  if (!collector) {
-    return NS_OK;
-  }
 
   if (eventType == kInput) {
-    collector->RecordInputChange();
+    change = Change::Input;
   } else if (eventType == kScroll) {
-    collector->RecordScrollChange();
+    change = Change::Scroll;
   }
 
+  RecordChange(windowContext, EnumSet(change));
+
   return NS_OK;
 }
 
@@ -128,13 +153,134 @@ void SessionStoreChangeListener::UpdateEventTargets() {
   AddEventListeners();
 }
 
-void SessionStoreChangeListener::Flush() {
+static void CollectFormData(Document* aDocument,
-  mBrowsingContext->FlushSessionStore();
+                            Maybe<sessionstore::FormData>& aFormData) {
+  aFormData.emplace();
+  auto& formData = aFormData.ref();
+  uint32_t size = SessionStoreUtils::CollectFormData(aDocument, formData);
+
+  Element* body = aDocument->GetBody();
+  if (aDocument->HasFlag(NODE_IS_EDITABLE) && body) {
+    IgnoredErrorResult result;
+    body->GetInnerHTML(formData.innerHTML(), result);
+    size += formData.innerHTML().Length();
+    if (!result.Failed()) {
+      formData.hasData() = true;
+    }
+  }
+
+  if (!formData.hasData()) {
+    return;
+  }
+
+  nsIURI* documentURI = aDocument->GetDocumentURI();
+  if (!documentURI) {
+    return;
+  }
+
+  documentURI->GetSpecIgnoringRef(formData.uri());
+
+  if (size > StaticPrefs::browser_sessionstore_dom_form_max_limit()) {
+    aFormData = Nothing();
+  }
+}
+
+void SessionStoreChangeListener::FlushSessionStore() {
+  if (mTimer) {
+    mTimer->Cancel();
+    mTimer = nullptr;
+  }
+
+  for (auto& iter : mSessionStoreChanges) {
+    WindowContext* windowContext = iter.GetKey();
+    if (!windowContext) {
+      continue;
+    }
+
+    RefPtr<Document> document = windowContext->GetDocument();
+    if (!document) {
+      continue;
+    }
+
+    EnumSet<Change> changes = iter.GetData();
+    Maybe<sessionstore::FormData> maybeFormData;
+    if (changes.contains(Change::Input)) {
+      CollectFormData(document, maybeFormData);
+    }
+
+    Maybe<nsPoint> maybeScroll;
+    PresShell* presShell = document->GetPresShell();
+
+    if (presShell && changes.contains(Change::Scroll)) {
+      maybeScroll = Some(presShell->GetVisualViewportOffset());
+    }
+
+    mSessionStoreChild->SendIncrementalSessionStoreUpdate(
+        windowContext->GetBrowsingContext(), maybeFormData, maybeScroll,
+        mEpoch);
+  }
+
+  mSessionStoreChanges.Clear();
+
+  mSessionStoreChild->UpdateSessionStore();
+}
+
+/* static */
+SessionStoreChangeListener* SessionStoreChangeListener::CollectSessionStoreData(
+    WindowContext* aWindowContext, const EnumSet<Change>& aChanges) {
+  SessionStoreChild* sessionStoreChild =
+      SessionStoreChild::From(aWindowContext->GetWindowGlobalChild());
+  if (!sessionStoreChild) {
+    return nullptr;
+  }
+
+  SessionStoreChangeListener* sessionStoreChangeListener =
+      sessionStoreChild->GetSessionStoreChangeListener();
+
+  if (!sessionStoreChangeListener) {
+    return nullptr;
+  }
+
+  sessionStoreChangeListener->RecordChange(aWindowContext, aChanges);
+
+  return sessionStoreChangeListener;
+}
+
+/* static */
+void SessionStoreChangeListener::FlushAllSessionStoreData(
+    WindowContext* aWindowContext) {
+  EnumSet<Change> allChanges(Change::Input, Change::Scroll);
+  SessionStoreChangeListener* listener =
+      CollectSessionStoreData(aWindowContext, allChanges);
+  if (listener) {
+    listener->FlushSessionStore();
+  }
+}
+
+void SessionStoreChangeListener::SetActor(
+    SessionStoreChild* aSessionStoreChild) {
+  mSessionStoreChild = aSessionStoreChild;
+}
+
+void SessionStoreChangeListener::RecordChange(WindowContext* aWindowContext,
+                                              EnumSet<Change> aChange) {
+  EnsureTimer();
+
+  Unused << mSessionStoreChanges.WithEntryHandle(
+      aWindowContext, [&](auto entryHandle) -> EnumSet<Change>& {
+        if (entryHandle) {
+          *entryHandle += aChange;
+          return *entryHandle;
+        }
+
+        return entryHandle.Insert(aChange);
+      });
 }
 
 SessionStoreChangeListener::SessionStoreChangeListener(
     BrowsingContext* aBrowsingContext)
-    : mBrowsingContext(aBrowsingContext) {}
+    : mBrowsingContext(aBrowsingContext),
+      mEpoch(aBrowsingContext->GetSessionStoreEpoch()) {}
 
 void SessionStoreChangeListener::Init() {
   AddEventListeners();
@@ -167,4 +313,19 @@ void SessionStoreChangeListener::RemoveEventListeners() {
   mCurrentEventTarget = nullptr;
 }
 
-}  // namespace mozilla::dom
+void SessionStoreChangeListener::EnsureTimer() {
+  if (mTimer) {
+    return;
+  }
+
+  if (!StaticPrefs::browser_sessionstore_debug_no_auto_updates()) {
+    auto result = NS_NewTimerWithCallback(
+        this, StaticPrefs::browser_sessionstore_interval(),
+        nsITimer::TYPE_ONE_SHOT);
+    if (result.isErr()) {
+      return;
+    }
+
+    mTimer = result.unwrap();
+  }
+}

toolkit/components/sessionstore/SessionStoreChangeListener.h

@@ -9,25 +9,39 @@
 
 #include "ErrorList.h"
 
+#include "PLDHashTable.h"
+#include "mozilla/EnumSet.h"
+#include "nsCycleCollectionParticipant.h"
+#include "nsHashKeys.h"
 #include "nsIDOMEventListener.h"
 #include "nsIObserver.h"
+#include "nsISupports.h"
+#include "nsITimer.h"
+#include "nsINamed.h"
+#include "nsHashtablesFwd.h"
 
-#include "nsCycleCollectionParticipant.h"
+#include "mozilla/EnumSet.h"
-
 #include "mozilla/RefPtr.h"
 #include "mozilla/Result.h"
 
+#include "mozilla/dom/WindowGlobalChild.h"
+
 namespace mozilla::dom {
 
+class BrowsingContext;
 class Element;
 class EventTarget;
-class SessionStoreDataCollector;
+class SessionStoreChild;
-class BrowsingContext;
+class WindowContext;
 
-class SessionStoreChangeListener final : public nsIObserver,
+class SessionStoreChangeListener final : public nsINamed,
+                                         public nsIObserver,
+                                         public nsITimerCallback,
                                          public nsIDOMEventListener {
  public:
+  NS_DECL_NSINAMED
   NS_DECL_NSIOBSERVER
+  NS_DECL_NSITIMERCALLBACK
   NS_DECL_NSIDOMEVENTLISTENER
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
   NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(SessionStoreChangeListener,
@@ -40,7 +54,29 @@ class SessionStoreChangeListener final : public nsIObserver,
 
   void UpdateEventTargets();
 
-  void Flush();
+  void FlushSessionStore();
+
+  enum class Change { None, Input, Scroll };
+
+  static SessionStoreChangeListener* CollectSessionStoreData(
+      WindowContext* aWindowContext, const EnumSet<Change>& aChanges);
+
+  static void FlushAllSessionStoreData(WindowContext* aWindowContext);
+
+  void SetActor(SessionStoreChild* aSessionStoreChild);
+
+  void SetEpoch(uint32_t aEpoch) { mEpoch = aEpoch; }
+
+  uint32_t GetEpoch() const { return mEpoch; }
+
+  BrowsingContext* GetBrowsingContext() const { return mBrowsingContext; }
+
+ private:
+  void RecordChange(WindowContext* aWindowContext, EnumSet<Change> aChanges);
+
+ public:
+  using SessionStoreChangeTable =
+      nsTHashMap<RefPtr<WindowContext>, EnumSet<Change>>;
 
  private:
   explicit SessionStoreChangeListener(BrowsingContext* aBrowsingContext);
@@ -53,8 +89,15 @@ class SessionStoreChangeListener final : public nsIObserver,
   void AddEventListeners();
   void RemoveEventListeners();
 
+  void EnsureTimer();
+
   RefPtr<BrowsingContext> mBrowsingContext;
   RefPtr<EventTarget> mCurrentEventTarget;
+
+  uint32_t mEpoch;
+  nsCOMPtr<nsITimer> mTimer;
+  RefPtr<SessionStoreChild> mSessionStoreChild;
+  SessionStoreChangeTable mSessionStoreChanges;
 };
 
 }  // namespace mozilla::dom

toolkit/components/sessionstore/SessionStoreChild.cpp

@@ -0,0 +1,226 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/dom/SessionStoreChild.h"
+
+#include "mozilla/AlreadyAddRefed.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/dom/BrowserChild.h"
+#include "mozilla/dom/BrowsingContext.h"
+#include "mozilla/dom/InProcessChild.h"
+#include "mozilla/dom/InProcessParent.h"
+#include "mozilla/dom/BrowserSessionStore.h"
+#include "mozilla/dom/SessionStoreChangeListener.h"
+#include "mozilla/dom/SessionStoreParent.h"
+#include "mozilla/dom/WindowGlobalParent.h"
+#include "mozilla/ipc/Endpoint.h"
+#include "nsCOMPtr.h"
+#include "nsFrameLoader.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
+
+class nsIDocShell;
+
+static already_AddRefed<TabListener> CreateTabListener(nsIDocShell* aDocShell) {
+  RefPtr<TabListener> tabListener =
+      mozilla::MakeRefPtr<TabListener>(aDocShell, nullptr);
+  nsresult rv = tabListener->Init();
+  if (NS_FAILED(rv)) {
+    return nullptr;
+  }
+
+  return tabListener.forget();
+}
+
+already_AddRefed<SessionStoreChild> SessionStoreChild::GetOrCreate(
+    BrowsingContext* aBrowsingContext, Element* aOwnerElement) {
+  RefPtr<TabListener> tabListener =
+      CreateTabListener(aBrowsingContext->GetDocShell());
+  if (!tabListener) {
+    return nullptr;
+  }
+
+  RefPtr<SessionStoreChangeListener> sessionStoreChangeListener =
+      SessionStoreChangeListener::Create(aBrowsingContext);
+  if (!sessionStoreChangeListener) {
+    return nullptr;
+  }
+
+  RefPtr<SessionStoreChild> sessionStoreChild =
+      new SessionStoreChild(tabListener, sessionStoreChangeListener);
+
+  sessionStoreChangeListener->SetActor(sessionStoreChild);
+
+  if (XRE_IsParentProcess()) {
+    MOZ_DIAGNOSTIC_ASSERT(aOwnerElement);
+    InProcessChild* inProcessChild = InProcessChild::Singleton();
+    InProcessParent* inProcessParent = InProcessParent::Singleton();
+    if (!inProcessChild || !inProcessParent) {
+      return nullptr;
+    }
+
+    RefPtr<BrowserSessionStore> sessionStore =
+        BrowserSessionStore::GetOrCreate(aBrowsingContext->Canonical()->Top());
+    if (!sessionStore) {
+      return nullptr;
+    }
+
+    CanonicalBrowsingContext* browsingContext = aBrowsingContext->Canonical();
+    RefPtr<SessionStoreParent> sessionStoreParent =
+        new SessionStoreParent(browsingContext, sessionStore);
+    ManagedEndpoint<PSessionStoreParent> endpoint =
+        inProcessChild->OpenPSessionStoreEndpoint(sessionStoreChild);
+    inProcessParent->BindPSessionStoreEndpoint(std::move(endpoint),
+                                               sessionStoreParent);
+  } else {
+    MOZ_DIAGNOSTIC_ASSERT(!aOwnerElement);
+    RefPtr<BrowserChild> browserChild =
+        BrowserChild::GetFrom(aBrowsingContext->GetDOMWindow());
+
+    MOZ_DIAGNOSTIC_ASSERT(browserChild);
+    MOZ_DIAGNOSTIC_ASSERT(aBrowsingContext->IsInProcess());
+    sessionStoreChild = static_cast<SessionStoreChild*>(
+        browserChild->SendPSessionStoreConstructor(sessionStoreChild));
+  }
+
+  return sessionStoreChild.forget();
+}
+
+/* static */
+SessionStoreChild* SessionStoreChild::From(WindowGlobalChild* aWindowChild) {
+  if (!aWindowChild) {
+    return nullptr;
+  }
+
+  // If `aWindowChild` is inprocess
+  if (RefPtr<BrowserChild> browserChild = aWindowChild->GetBrowserChild()) {
+    return browserChild->GetSessionStoreChild();
+  }
+
+  if (XRE_IsContentProcess()) {
+    return nullptr;
+  }
+
+  WindowGlobalParent* windowParent = aWindowChild->WindowContext()->Canonical();
+  if (!windowParent) {
+    return nullptr;
+  }
+
+  RefPtr<nsFrameLoader> frameLoader = windowParent->GetRootFrameLoader();
+  if (!frameLoader) {
+    return nullptr;
+  }
+
+  return frameLoader->GetSessionStoreChild();
+}
+
+SessionStoreChild::SessionStoreChild(
+    TabListener* aSessionStoreListener,
+    SessionStoreChangeListener* aSessionStoreChangeListener)
+    : mSessionStoreListener(aSessionStoreListener),
+      mSessionStoreChangeListener(aSessionStoreChangeListener) {}
+
+void SessionStoreChild::SetEpoch(uint32_t aEpoch) {
+  if (mSessionStoreListener) {
+    mSessionStoreListener->SetEpoch(aEpoch);
+  }
+
+  if (mSessionStoreChangeListener) {
+    mSessionStoreChangeListener->SetEpoch(aEpoch);
+  }
+}
+
+void SessionStoreChild::SetOwnerContent(Element* aElement) {
+  if (mSessionStoreChangeListener) {
+    mSessionStoreChangeListener->FlushSessionStore();
+  }
+
+  if (!aElement) {
+    return;
+  }
+
+  if (mSessionStoreListener) {
+    mSessionStoreListener->SetOwnerContent(aElement);
+  }
+}
+
+void SessionStoreChild::Stop() {
+  if (mSessionStoreListener) {
+    mSessionStoreListener->RemoveListeners();
+    mSessionStoreListener = nullptr;
+  }
+
+  if (mSessionStoreChangeListener) {
+    mSessionStoreChangeListener->Stop();
+  }
+}
+
+void SessionStoreChild::UpdateEventTargets() {
+  if (mSessionStoreChangeListener) {
+    mSessionStoreChangeListener->UpdateEventTargets();
+  }
+}
+
+void SessionStoreChild::UpdateSessionStore() {
+  if (!mSessionStoreListener) {
+    // This is the case when we're shutting down, and expect a final update.
+    Unused << SendSessionStoreUpdate(Nothing(), Nothing(), false, 0);
+    return;
+  }
+
+  RefPtr<ContentSessionStore> store = mSessionStoreListener->GetSessionStore();
+
+  Maybe<nsCString> docShellCaps;
+  if (store->IsDocCapChanged()) {
+    docShellCaps.emplace(store->GetDocShellCaps());
+  }
+
+  Maybe<bool> privatedMode;
+  if (store->IsPrivateChanged()) {
+    privatedMode.emplace(store->GetPrivateModeEnabled());
+  }
+
+  Unused << SendSessionStoreUpdate(docShellCaps, privatedMode,
+                                   store->GetAndClearSHistoryChanged(),
+                                   mSessionStoreListener->GetEpoch());
+}
+
+void SessionStoreChild::FlushSessionStore() {
+  if (mSessionStoreChangeListener) {
+    mSessionStoreChangeListener->FlushSessionStore();
+  }
+}
+
+void SessionStoreChild::UpdateSHistoryChanges() {
+  if (mSessionStoreListener) {
+    mSessionStoreListener->UpdateSHistoryChanges();
+  }
+}
+
+mozilla::ipc::IPCResult SessionStoreChild::RecvFlushTabState(
+    FlushTabStateResolver&& aResolver) {
+  if (mSessionStoreChangeListener) {
+    if (BrowsingContext* context =
+            mSessionStoreChangeListener->GetBrowsingContext()) {
+      if (auto* docShell = nsDocShell::Cast(context->GetDocShell())) {
+        docShell->CollectWireframe();
+      }
+    }
+
+    mSessionStoreChangeListener->FlushSessionStore();
+  }
+  aResolver(true);
+
+  return IPC_OK();
+}
+
+NS_IMPL_CYCLE_COLLECTION(SessionStoreChild, mSessionStoreListener,
+                         mSessionStoreChangeListener)
+NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(SessionStoreChild, AddRef)
+NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(SessionStoreChild, Release)

toolkit/components/sessionstore/SessionStoreChild.h

@@ -0,0 +1,57 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_dom_SessionStoreChild_h
+#define mozilla_dom_SessionStoreChild_h
+
+#include "mozilla/AlreadyAddRefed.h"
+#include "mozilla/dom/PSessionStoreChild.h"
+#include "mozilla/dom/SessionStoreChangeListener.h"
+#include "mozilla/dom/SessionStoreListener.h"
+#include "mozilla/RefPtr.h"
+
+#include "nsCycleCollectionParticipant.h"
+
+namespace mozilla::dom {
+class BrowsingContext;
+class SessionStoreChangeListener;
+class TabListener;
+
+class SessionStoreChild final : public PSessionStoreChild {
+ public:
+  static already_AddRefed<SessionStoreChild> GetOrCreate(
+      BrowsingContext* aBrowsingContext, Element* aOwnerElement = nullptr);
+
+  static SessionStoreChild* From(WindowGlobalChild* aWindowChild);
+
+  void SetEpoch(uint32_t aEpoch);
+  void SetOwnerContent(Element* aElement);
+  void Stop();
+  void UpdateEventTargets();
+  void UpdateSessionStore();
+  void FlushSessionStore();
+  void UpdateSHistoryChanges();
+
+  SessionStoreChangeListener* GetSessionStoreChangeListener() const {
+    return mSessionStoreChangeListener;
+  }
+
+  mozilla::ipc::IPCResult RecvFlushTabState(FlushTabStateResolver&& aResolver);
+
+  NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(SessionStoreChild)
+  NS_DECL_CYCLE_COLLECTION_NATIVE_CLASS(SessionStoreChild)
+
+ private:
+  SessionStoreChild(TabListener* aSessionStoreListener,
+                    SessionStoreChangeListener* aSessionStoreChangeListener);
+  ~SessionStoreChild() = default;
+
+  RefPtr<TabListener> mSessionStoreListener;
+  RefPtr<SessionStoreChangeListener> mSessionStoreChangeListener;
+};
+}  // namespace mozilla::dom
+
+#endif  // mozilla_dom_SessionStoreChild_h

toolkit/components/sessionstore/SessionStoreDataCollector.cpp

@@ -1,180 +0,0 @@
-/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* vim: set ts=8 sts=2 et sw=2 tw=80: */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#include "mozilla/dom/SessionStoreDataCollector.h"
-
-#include "mozilla/Assertions.h"
-#include "mozilla/PresShell.h"
-#include "mozilla/dom/BrowserChild.h"
-#include "mozilla/dom/BrowsingContext.h"
-#include "mozilla/dom/Document.h"
-#include "mozilla/dom/Element.h"
-#include "mozilla/dom/sessionstore/SessionStoreTypes.h"
-#include "mozilla/dom/SessionStoreUtils.h"
-#include "mozilla/dom/WindowGlobalChild.h"
-#include "mozilla/dom/WindowGlobalParent.h"
-
-#include "nsGenericHTMLElement.h"
-#include "nsIContentInlines.h"
-
-namespace mozilla::dom {
-
-NS_IMPL_CYCLE_COLLECTION(SessionStoreDataCollector, mWindowChild, mTimer)
-
-NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(SessionStoreDataCollector)
-  NS_INTERFACE_MAP_ENTRY(nsITimerCallback)
-  NS_INTERFACE_MAP_ENTRY(nsINamed)
-  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsITimerCallback)
-NS_INTERFACE_MAP_END
-
-NS_IMPL_CYCLE_COLLECTING_ADDREF(SessionStoreDataCollector)
-NS_IMPL_CYCLE_COLLECTING_RELEASE(SessionStoreDataCollector)
-
-NS_IMETHODIMP
-SessionStoreDataCollector::GetName(nsACString& aName) {
-  aName.AssignLiteral("SessionStoreDataCollector");
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-SessionStoreDataCollector::Notify(nsITimer* aTimer) {
-  Collect();
-  return NS_OK;
-}
-
-/* static */ already_AddRefed<SessionStoreDataCollector>
-SessionStoreDataCollector::CollectSessionStoreData(
-    WindowGlobalChild* aWindowChild) {
-  MOZ_RELEASE_ASSERT(SessionStoreUtils::NATIVE_LISTENER);
-  MOZ_DIAGNOSTIC_ASSERT(aWindowChild);
-
-  RefPtr<SessionStoreDataCollector> listener =
-      aWindowChild->GetSessionStoreDataCollector();
-
-  uint32_t epoch =
-      aWindowChild->BrowsingContext()->Top()->GetSessionStoreEpoch();
-  if (listener) {
-    MOZ_DIAGNOSTIC_ASSERT_IF(
-        !StaticPrefs::browser_sessionstore_debug_no_auto_updates(),
-        listener->mTimer);
-    if (listener->mEpoch == epoch) {
-      return listener.forget();
-    }
-    if (listener->mTimer) {
-      listener->mTimer->Cancel();
-    }
-  }
-
-  listener = new SessionStoreDataCollector(aWindowChild, epoch);
-
-  if (!StaticPrefs::browser_sessionstore_debug_no_auto_updates()) {
-    auto result = NS_NewTimerWithCallback(
-        listener, StaticPrefs::browser_sessionstore_interval(),
-        nsITimer::TYPE_ONE_SHOT);
-    if (result.isErr()) {
-      return nullptr;
-    }
-
-    listener->mTimer = result.unwrap();
-  }
-
-  aWindowChild->SetSessionStoreDataCollector(listener);
-  return listener.forget();
-}
-
-void SessionStoreDataCollector::RecordInputChange() { mInputChanged = true; }
-
-void SessionStoreDataCollector::RecordScrollChange() { mScrollChanged = true; }
-
-void SessionStoreDataCollector::Flush() { Collect(); }
-
-void SessionStoreDataCollector::Cancel() {
-  if (mTimer) {
-    mTimer->Cancel();
-    mTimer = nullptr;
-  }
-
-  mWindowChild->SetSessionStoreDataCollector(nullptr);
-}
-
-void SessionStoreDataCollector::Collect() {
-  if (this != mWindowChild->GetSessionStoreDataCollector()) {
-    return;
-  }
-
-  if (mTimer) {
-    mTimer->Cancel();
-    mTimer = nullptr;
-  }
-
-  nsGlobalWindowInner* inner = mWindowChild->GetWindowGlobal();
-  if (!inner) {
-    return;
-  }
-
-  Document* document = inner->GetDocument();
-  if (!document) {
-    return;
-  }
-
-  Maybe<sessionstore::FormData> maybeFormData;
-  if (mInputChanged) {
-    maybeFormData.emplace();
-    auto& formData = maybeFormData.ref();
-    uint32_t size = SessionStoreUtils::CollectFormData(document, formData);
-
-    Element* body = document->GetBody();
-    if (body && body->IsInDesignMode()) {
-      IgnoredErrorResult result;
-      body->GetInnerHTML(formData.innerHTML(), result);
-      size += formData.innerHTML().Length();
-      if (!result.Failed()) {
-        formData.hasData() = true;
-      }
-    }
-
-    if (size > StaticPrefs::browser_sessionstore_dom_form_max_limit()) {
-      maybeFormData = Nothing();
-    }
-  }
-
-  PresShell* presShell = document->GetPresShell();
-  Maybe<nsPoint> maybeScroll;
-  if (mScrollChanged && presShell) {
-    maybeScroll = Some(presShell->GetVisualViewportOffset());
-  }
-
-  if (!mWindowChild->CanSend()) {
-    return;
-  }
-
-  if (RefPtr<WindowGlobalParent> windowParent =
-          mWindowChild->GetParentActor()) {
-    windowParent->WriteFormDataAndScrollToSessionStore(maybeFormData,
-                                                       maybeScroll, mEpoch);
-  } else {
-    mWindowChild->SendUpdateSessionStore(maybeFormData, maybeScroll, mEpoch);
-  }
-
-  mWindowChild->SetSessionStoreDataCollector(nullptr);
-}
-
-SessionStoreDataCollector::SessionStoreDataCollector(
-    WindowGlobalChild* aWindowChild, uint32_t aEpoch)
-    : mWindowChild(aWindowChild),
-      mTimer(nullptr),
-      mEpoch(aEpoch),
-      mInputChanged(false),
-      mScrollChanged(false) {}
-
-SessionStoreDataCollector::~SessionStoreDataCollector() {
-  if (mTimer) {
-    mTimer->Cancel();
-    mTimer = nullptr;
-  }
-}
-
-}  // namespace mozilla::dom

toolkit/components/sessionstore/SessionStoreDataCollector.h

@@ -1,68 +0,0 @@
-/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* vim: set ts=8 sts=2 et sw=2 tw=80: */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#ifndef mozilla_dom_SessionStoreDataCollector_h
-#define mozilla_dom_SessionStoreDataCollector_h
-
-#include "ErrorList.h"
-
-#include "nsITimer.h"
-
-#include "nsCycleCollectionParticipant.h"
-
-#include "mozilla/RefPtr.h"
-
-namespace mozilla::dom {
-
-class BrowserChild;
-class EventTarget;
-class WindowGlobalChild;
-
-namespace sessionstore {
-class FormData;
-}
-
-class SessionStoreDataCollector final : public nsITimerCallback,
-                                        public nsINamed {
- public:
-  NS_DECL_NSITIMERCALLBACK
-  NS_DECL_NSINAMED
-  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
-  NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(SessionStoreDataCollector,
-                                           nsITimerCallback)
-
-  enum class Change { Input, Scroll };
-
-  static already_AddRefed<SessionStoreDataCollector> CollectSessionStoreData(
-      WindowGlobalChild* aWindowChild);
-
-  void RecordInputChange();
-  void RecordScrollChange();
-
-  void Flush();
-
-  void Cancel();
-
- private:
-  void Collect();
-
-  nsresult Apply(Maybe<sessionstore::FormData>&& aFormData,
-                 Maybe<nsPoint>&& aScroll);
-
-  SessionStoreDataCollector(WindowGlobalChild* aWindowChild, uint32_t aEpoch);
-  ~SessionStoreDataCollector();
-
-  RefPtr<WindowGlobalChild> mWindowChild;
-  nsCOMPtr<nsITimer> mTimer;
-
-  uint32_t mEpoch;
-  bool mInputChanged : 1;
-  bool mScrollChanged : 1;
-};
-
-}  // namespace mozilla::dom
-
-#endif  // mozilla_dom_SessionStoreDataCollector_h

toolkit/components/sessionstore/SessionStoreFormData.cpp

@@ -0,0 +1,172 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/dom/SessionStoreFormData.h"
+
+#include "mozilla/Assertions.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/dom/BindingUtils.h"
+#include "mozilla/dom/BrowserSessionStoreBinding.h"
+#include "mozilla/dom/BrowsingContext.h"
+#include "mozilla/dom/sessionstore/SessionStoreTypes.h"
+
+#include "nsContentUtils.h"
+#include "js/JSON.h"
+
+using namespace mozilla::dom;
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(SessionStoreFormData)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(SessionStoreFormData)
+
+NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_WEAK_PTR(SessionStoreFormData, mChildren)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(SessionStoreFormData)
+  NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
+  NS_INTERFACE_MAP_ENTRY(nsISupports)
+NS_INTERFACE_MAP_END
+
+nsISupports* SessionStoreFormData::GetParentObject() const {
+  return xpc::NativeGlobal(xpc::PrivilegedJunkScope());
+}
+
+JSObject* SessionStoreFormData::WrapObject(JSContext* aCx,
+                                           JS::Handle<JSObject*> aGivenProto) {
+  return SessionStoreFormData_Binding::Wrap(aCx, this, aGivenProto);
+}
+
+void SessionStoreFormData::GetUrl(nsACString& aUrl) const {
+  if (mUrl.IsEmpty()) {
+    aUrl.SetIsVoid(true);
+  } else {
+    aUrl = mUrl;
+  }
+}
+
+void SessionStoreFormData::GetId(
+    JSContext* aCx,
+    Nullable<Record<nsString, OwningStringOrBooleanOrObject>>& aId) {
+  if (mId.IsEmpty() ||
+      NS_FAILED(SessionStoreUtils::ConstructFormDataValues(
+          aCx, mId, aId.SetValue().Entries(), mParseSessionData))) {
+    aId.SetNull();
+  }
+
+  // SessionStoreFormData.id is now stored in a slot, so we can free our
+  // internal state.
+  mId.Clear();
+}
+
+void SessionStoreFormData::GetXpath(
+    JSContext* aCx,
+    Nullable<Record<nsString, OwningStringOrBooleanOrObject>>& aXpath) {
+  if (mXpath.IsEmpty() ||
+      NS_FAILED(SessionStoreUtils::ConstructFormDataValues(
+          aCx, mXpath, aXpath.SetValue().Entries(), mParseSessionData))) {
+    aXpath.SetNull();
+  }
+
+  // SessionStoreFormData.xpath is now stored in a slot, so we can free our
+  // internal state.
+  mXpath.Clear();
+}
+
+void SessionStoreFormData::GetInnerHTML(nsAString& aInnerHTML) {
+  if (mInnerHTML.IsEmpty()) {
+    SetDOMStringToNull(aInnerHTML);
+  } else {
+    aInnerHTML = mInnerHTML;
+  }
+
+  // SessionStoreFormData.innerHTML is now stored in a slot, so we can free our
+  // internal state.
+  mInnerHTML.SetIsVoid(true);
+}
+
+SessionStoreFormData::ChildrenArray& SessionStoreFormData::Children() {
+  return mChildren;
+}
+
+void SessionStoreFormData::GetChildren(
+    Nullable<ChildrenArray>& aChildren) const {
+  if (!mChildren.IsEmpty()) {
+    aChildren.SetValue() = mChildren.Clone();
+  } else {
+    aChildren.SetNull();
+  }
+}
+
+void SessionStoreFormData::ToJSON(JSContext* aCx,
+                                  JS::MutableHandleObject aRetval) {
+  JS::RootedObject self(aCx);
+  {
+    JS::RootedValue value(aCx);
+    if (!GetOrCreateDOMReflector(aCx, this, &value)) {
+      return;
+    }
+
+    self.set(value.toObjectOrNull());
+  }
+
+  JS::Rooted<JSObject*> result(aCx, JS_NewPlainObject(aCx));
+
+  if (!IsEmpty()) {
+    for (const auto& name :
+         {u"url"_ns, u"id"_ns, u"xpath"_ns, u"innerHTML"_ns}) {
+      if (!SessionStoreUtils::CopyProperty(aCx, result, self, name)) {
+        return;
+      }
+    }
+
+    SessionStoreUtils::CopyChildren(aCx, result, mChildren);
+  }
+
+  aRetval.set(result);
+}
+
+void SessionStoreFormData::Update(const CollectedType& aFormData) {
+  SessionStoreFormData_Binding::ClearCachedUrlValue(this);
+  SessionStoreFormData_Binding::ClearCachedIdValue(this);
+  SessionStoreFormData_Binding::ClearCachedXpathValue(this);
+  SessionStoreFormData_Binding::ClearCachedInnerHTMLValue(this);
+
+  if (!aFormData.hasData()) {
+    mParseSessionData = false;
+    mHasData = false;
+    mUrl = ""_ns;
+    mId.Clear();
+    mXpath.Clear();
+    mInnerHTML = u""_ns;
+
+    return;
+  }
+
+  mHasData = true;
+
+  mUrl = aFormData.uri();
+  // We want to avoid saving data for about:sessionrestore as a string.
+  // Since it's stored in the form as stringified JSON, stringifying
+  // further causes an explosion of escape characters. cf. bug 467409
+  mParseSessionData =
+      mUrl == "about:sessionrestore"_ns || mUrl == "about:welcomeback"_ns;
+
+  mInnerHTML = aFormData.innerHTML();
+
+  mId.Assign(aFormData.id());
+  mXpath.Assign(aFormData.xpath());
+}
+
+void SessionStoreFormData::ClearCachedChildren() {
+  SessionStoreFormData_Binding::ClearCachedChildrenValue(this);
+}
+
+/* static */ bool SessionStoreFormData::HasData(
+    const CollectedType& aFormData) {
+  return aFormData.hasData();
+}
+
+bool SessionStoreFormData::IsEmpty() const {
+  return !mHasData && mChildren.IsEmpty();
+}

toolkit/components/sessionstore/SessionStoreFormData.h

@@ -0,0 +1,83 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_dom_SessionStoreFormData_h
+#define mozilla_dom_SessionStoreFormData_h
+
+#include "mozilla/WeakPtr.h"
+#include "mozilla/dom/UnionTypes.h"
+#include "mozilla/dom/WindowGlobalParent.h"
+
+#include "nsTArrayForwardDeclare.h"
+#include "nsWrapperCache.h"
+
+class nsIGlobalObject;
+
+namespace mozilla::dom {
+
+namespace sessionstore {
+class FormData;
+}
+
+class BrowsingContext;
+class OwningByteStringOrObjectOrNull;
+class OwningStringOrObjectOrNull;
+class WindowGlobalParent;
+
+class SessionStoreFormData final : public nsISupports,
+                                   public nsWrapperCache,
+                                   public SupportsWeakPtr {
+ public:
+  using CollectedType = sessionstore::FormData;
+  using LocationType = WeakPtr<SessionStoreFormData>;
+  using ChildrenArray = nsTArray<RefPtr<SessionStoreFormData>>;
+
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(SessionStoreFormData)
+  nsISupports* GetParentObject() const;
+  JSObject* WrapObject(JSContext* aCx,
+                       JS::Handle<JSObject*> aGivenProto) override;
+
+  void GetUrl(nsACString& aUrl) const;
+
+  void GetId(JSContext* aCx,
+             Nullable<Record<nsString, OwningStringOrBooleanOrObject>>& aId);
+
+  void GetXpath(
+      JSContext* aCx,
+      Nullable<Record<nsString, OwningStringOrBooleanOrObject>>& aXpath);
+
+  void GetInnerHTML(nsAString& aInnerHTML);
+
+  ChildrenArray& Children();
+
+  void GetChildren(Nullable<ChildrenArray>& aChildren) const;
+
+  void ToJSON(JSContext* aCx, JS::MutableHandleObject aRetval);
+
+  void Update(const CollectedType& aFormData);
+
+  void ClearCachedChildren();
+
+  static bool HasData(const CollectedType& aFormData);
+
+  bool IsEmpty() const;
+
+ private:
+  ~SessionStoreFormData() = default;
+
+  bool mParseSessionData = false;
+  bool mHasData = false;
+  nsCString mUrl;
+  nsTArray<sessionstore::FormEntry> mId;
+  nsTArray<sessionstore::FormEntry> mXpath;
+  nsString mInnerHTML;
+  ChildrenArray mChildren;
+};
+
+}  // namespace mozilla::dom
+
+#endif  // mozilla_dom_SessionStoreFormData_h

toolkit/components/sessionstore/SessionStoreFunctions.idl

@@ -17,10 +17,6 @@ interface nsISessionStoreFunctions : nsISupports {
     in jsval aPermanentKey, in uint32_t aEpoch, in boolean aCollectSHistory,
     in jsval aData);
 
-  void UpdateSessionStoreForWindow(
-    in Element aBrowser, in BrowsingContext aBrowsingContext,
-    in jsval aPermanentKey, in uint32_t aEpoch, in jsval aData);
-
   void UpdateSessionStoreForStorage(
     in Element aBrowser, in BrowsingContext aBrowsingContext,
     in jsval aPermanentKey, in uint32_t aEpoch, in jsval aData);

toolkit/components/sessionstore/SessionStoreFunctions.jsm

@@ -28,22 +28,6 @@ function UpdateSessionStore(
   );
 }
 
-function UpdateSessionStoreForWindow(
-  aBrowser,
-  aBrowsingContext,
-  aPermanentKey,
-  aEpoch,
-  aData
-) {
-  return SessionStoreFuncInternal.updateSessionStoreForWindow(
-    aBrowser,
-    aBrowsingContext,
-    aPermanentKey,
-    aEpoch,
-    aData
-  );
-}
-
 function UpdateSessionStoreForStorage(
   aBrowser,
   aBrowsingContext,
@@ -60,11 +44,7 @@ function UpdateSessionStoreForStorage(
   );
 }
 
-var EXPORTED_SYMBOLS = [
+var EXPORTED_SYMBOLS = ["UpdateSessionStore", "UpdateSessionStoreForStorage"];
-  "UpdateSessionStore",
-  "UpdateSessionStoreForWindow",
-  "UpdateSessionStoreForStorage",
-];
 
 var SessionStoreFuncInternal = {
   updateSessionStore: function SSF_updateSessionStore(
@@ -75,12 +55,14 @@ var SessionStoreFuncInternal = {
     aCollectSHistory,
     aData
   ) {
-    let currentData = {};
+    let { formdata, scroll } = aData;
-    if (aData.docShellCaps != undefined) {
+
-      currentData.disallow = aData.docShellCaps ? aData.docShellCaps : null;
+    if (formdata) {
+      aData.formdata = formdata.toJSON();
     }
-    if (aData.isPrivate != undefined) {
+
-      currentData.isPrivate = aData.isPrivate;
+    if (scroll) {
+      aData.scroll = scroll.toJSON();
     }
 
     SessionStore.updateSessionStoreFromTablistener(
@@ -88,28 +70,13 @@ var SessionStoreFuncInternal = {
       aBrowsingContext,
       aPermanentKey,
       {
-        data: currentData,
+        data: aData,
         epoch: aEpoch,
         sHistoryNeeded: aCollectSHistory,
       }
     );
   },
 
-  updateSessionStoreForWindow: function SSF_updateSessionStoreForWindow(
-    aBrowser,
-    aBrowsingContext,
-    aPermanentKey,
-    aEpoch,
-    aData
-  ) {
-    SessionStore.updateSessionStoreFromTablistener(
-      aBrowser,
-      aBrowsingContext,
-      aPermanentKey,
-      { data: { windowstatechange: aData }, epoch: aEpoch }
-    );
-  },
-
   updateSessionStoreForStorage: function SSF_updateSessionStoreForWindow(
     aBrowser,
     aBrowsingContext,

toolkit/components/sessionstore/SessionStoreListener.cpp

@@ -3,6 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "mozilla/PresShell.h"
+#include "mozilla/dom/BrowserSessionStoreBinding.h"
 #include "mozilla/dom/Document.h"
 #include "mozilla/dom/SessionStoreListener.h"
 #include "mozilla/dom/SessionStoreUtils.h"
@@ -384,20 +385,21 @@ nsresult TabListener::Observe(nsISupports* aSubject, const char* aTopic,
   return NS_ERROR_UNEXPECTED;
 }
 
-bool TabListener::ForceFlushFromParent() {
+void TabListener::ForceFlushFromParent() {
   if (!XRE_IsParentProcess()) {
-    return false;
+    return;
   }
   if (!mSessionStore) {
-    return false;
+    return;
   }
-  return UpdateSessionStore(true);
+
+  UpdateSessionStore(true);
 }
 
-bool TabListener::UpdateSessionStore(bool aIsFlush) {
+void TabListener::UpdateSessionStore(bool aIsFlush) {
   if (!aIsFlush) {
     if (!mSessionStore || !mSessionStore->UpdateNeeded()) {
-      return false;
+      return;
     }
   }
 
@@ -405,33 +407,33 @@ bool TabListener::UpdateSessionStore(bool aIsFlush) {
     BrowserChild* browserChild = BrowserChild::GetFrom(mDocShell);
     if (browserChild) {
       StopTimerForUpdate();
-      return browserChild->UpdateSessionStore();
+      browserChild->UpdateSessionStore();
     }
-    return false;
+    return;
   }
 
   BrowsingContext* context = mDocShell->GetBrowsingContext();
   if (!context) {
-    return false;
+    return;
   }
 
   uint32_t chromeFlags = 0;
   nsCOMPtr<nsIDocShellTreeOwner> treeOwner;
   mDocShell->GetTreeOwner(getter_AddRefs(treeOwner));
   if (!treeOwner) {
-    return false;
+    return;
   }
   nsCOMPtr<nsIAppWindow> window(do_GetInterface(treeOwner));
   if (!window) {
-    return false;
+    return;
   }
   if (window && NS_FAILED(window->GetChromeFlags(&chromeFlags))) {
-    return false;
+    return;
   }
 
   UpdateSessionStoreData data;
   if (mSessionStore->IsDocCapChanged()) {
-    data.mDocShellCaps.Construct() = mSessionStore->GetDocShellCaps();
+    data.mDisallow.Construct() = mSessionStore->GetDocShellCaps();
   }
   if (mSessionStore->IsPrivateChanged()) {
     data.mIsPrivate.Construct() = mSessionStore->GetPrivateModeEnabled();
@@ -440,16 +442,18 @@ bool TabListener::UpdateSessionStore(bool aIsFlush) {
   nsCOMPtr<nsISessionStoreFunctions> funcs = do_ImportModule(
       "resource://gre/modules/SessionStoreFunctions.jsm", fallible);
   nsCOMPtr<nsIXPConnectWrappedJS> wrapped = do_QueryInterface(funcs);
-  NS_ENSURE_TRUE(wrapped, false);
+  if (!wrapped) {
+    return;
+  }
 
   AutoJSAPI jsapi;
   if (!jsapi.Init(wrapped->GetJSObjectGlobal())) {
-    return false;
+    return;
   }
 
   JS::Rooted<JS::Value> update(jsapi.cx());
   if (!ToJSValue(jsapi.cx(), data, &update)) {
-    return false;
+    return;
   }
 
   JS::RootedValue key(jsapi.cx(), context->Canonical()->Top()->PermanentKey());
@@ -458,11 +462,10 @@ bool TabListener::UpdateSessionStore(bool aIsFlush) {
       mOwnerContent, context, key, mEpoch,
       mSessionStore->GetAndClearSHistoryChanged(), update);
   if (NS_FAILED(rv)) {
-    return false;
+    return;
   }
 
   StopTimerForUpdate();
-  return true;
 }
 
 void TabListener::RemoveListeners() {

toolkit/components/sessionstore/SessionStoreListener.h

@@ -73,7 +73,7 @@ class TabListener : public nsIDOMEventListener,
   nsresult Init();
   ContentSessionStore* GetSessionStore() { return mSessionStore; }
   // the function is called only when TabListener is in parent process
-  bool ForceFlushFromParent();
+  void ForceFlushFromParent();
   void RemoveListeners();
   void SetEpoch(uint32_t aEpoch) { mEpoch = aEpoch; }
   uint32_t GetEpoch() { return mEpoch; }
@@ -94,7 +94,7 @@ class TabListener : public nsIDOMEventListener,
   void StopTimerForUpdate();
   void AddEventListeners();
   void RemoveEventListeners();
-  bool UpdateSessionStore(bool aIsFlush = false);
+  void UpdateSessionStore(bool aIsFlush = false);
   virtual ~TabListener();
 
   nsCOMPtr<nsIDocShell> mDocShell;

toolkit/components/sessionstore/SessionStoreMessageUtils.h

@@ -6,6 +6,7 @@
 #define mozilla_dom_SessionStoreMessageUtils_h
 
 #include "ipc/IPCMessageUtils.h"
+#include "mozilla/ipc/IPDLParamTraits.h"
 #include "SessionStoreData.h"
 #include "SessionStoreUtils.h"
 #include "SessionStoreRestoreData.h"

toolkit/components/sessionstore/SessionStoreParent.cpp

@@ -0,0 +1,194 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/dom/SessionStoreParent.h"
+
+#include "mozilla/AlreadyAddRefed.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/dom/BrowserParent.h"
+#include "mozilla/dom/BrowserSessionStore.h"
+#include "mozilla/dom/BrowserSessionStoreBinding.h"
+#include "mozilla/dom/BrowsingContext.h"
+#include "mozilla/dom/InProcessChild.h"
+#include "mozilla/dom/InProcessParent.h"
+#include "mozilla/dom/SessionStoreChild.h"
+#include "mozilla/dom/SessionStoreUtilsBinding.h"
+#include "SessionStoreFunctions.h"
+#include "nsISupports.h"
+#include "nsIXULRuntime.h"
+#include "nsImportModule.h"
+#include "nsIXPConnect.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
+
+SessionStoreParent::SessionStoreParent(
+    CanonicalBrowsingContext* aBrowsingContext,
+    BrowserSessionStore* aSessionStore)
+    : mBrowsingContext(aBrowsingContext), mSessionStore(aSessionStore) {}
+
+static void SessionStoreUpdate(CanonicalBrowsingContext* aBrowsingContext,
+                               const Maybe<nsCString>& aDocShellCaps,
+                               const Maybe<bool>& aPrivatedMode,
+                               bool aNeedCollectSHistory, uint32_t aEpoch) {
+  UpdateSessionStoreData data;
+  if (aDocShellCaps.isSome()) {
+    auto& disallow = data.mDisallow.Construct();
+    if (!aDocShellCaps->IsEmpty()) {
+      disallow = aDocShellCaps.value();
+    } else {
+      disallow.SetIsVoid(true);
+    }
+  }
+
+  if (aPrivatedMode.isSome()) {
+    data.mIsPrivate.Construct() = aPrivatedMode.value();
+  }
+
+  RefPtr<BrowserSessionStore> sessionStore =
+      BrowserSessionStore::GetOrCreate(aBrowsingContext->Top());
+
+  SessionStoreFormData* formData = sessionStore->GetFormdata();
+  data.mFormdata.Construct(formData);
+
+  SessionStoreScrollData* scroll = sessionStore->GetScroll();
+  data.mScroll.Construct(scroll);
+
+  nsCOMPtr<nsISessionStoreFunctions> funcs = do_ImportModule(
+      "resource://gre/modules/SessionStoreFunctions.jsm", fallible);
+  nsCOMPtr<nsIXPConnectWrappedJS> wrapped = do_QueryInterface(funcs);
+  if (!wrapped) {
+    return;
+  }
+
+  AutoJSAPI jsapi;
+  if (!jsapi.Init(wrapped->GetJSObjectGlobal())) {
+    return;
+  }
+
+  JS::Rooted<JS::Value> update(jsapi.cx());
+  if (!ToJSValue(jsapi.cx(), data, &update)) {
+    return;
+  }
+
+  JS::RootedValue key(jsapi.cx(), aBrowsingContext->Top()->PermanentKey());
+
+  Unused << funcs->UpdateSessionStore(nullptr, aBrowsingContext, key, aEpoch,
+                                      aNeedCollectSHistory, update);
+}
+
+void SessionStoreParent::FlushAllSessionStoreChildren(
+    const std::function<void()>& aDone) {
+  if (!mBrowsingContext) {
+    aDone();
+    return;
+  }
+
+  nsTArray<RefPtr<SessionStoreParent::FlushTabStatePromise>> flushPromises;
+
+  // We're special casing this for when the SessionStore{Child, Parent} have
+  // been created in the same process. This is only ever true for the parent
+  // process session store actor, and is needed because
+  // nsFrameLoader::RequestTabStateFlush expect flushes to happen faster than we
+  // can manage by using the common path of sending a message the
+  // SessionStoreChild. Ideally we should be able to do just that, but not
+  // without more work.
+  if (InProcessParent::ChildActorFor(this)) {
+    // Here we assume that the session store data collection only collect for in
+    // (parent-)process content type browsing contexts, which we only flush one
+    // session store actor.
+    flushPromises.AppendElement(FlushSessionStore());
+  } else {
+    // While here we flush all participating actors.
+    BrowserParent* browserParent = static_cast<BrowserParent*>(Manager());
+    browserParent->VisitAll([&flushPromises](BrowserParent* aBrowser) {
+      if (PSessionStoreParent* sessionStoreParent =
+              SingleManagedOrNull(aBrowser->ManagedPSessionStoreParent())) {
+        flushPromises.AppendElement(
+            static_cast<SessionStoreParent*>(sessionStoreParent)
+                ->FlushSessionStore());
+      }
+    });
+  }
+
+  RefPtr<SessionStoreParent::FlushTabStatePromise::AllPromiseType>
+      flushPromise = SessionStoreParent::FlushTabStatePromise::All(
+          GetMainThreadSerialEventTarget(), flushPromises);
+
+  mBrowsingContext->UpdateSessionStoreSessionStorage([aDone, flushPromise]() {
+    flushPromise->Then(GetCurrentSerialEventTarget(), __func__,
+                       [aDone]() { aDone(); });
+  });
+}
+
+already_AddRefed<SessionStoreParent::FlushTabStatePromise>
+SessionStoreParent::FlushSessionStore() {
+  if (!mBrowsingContext) {
+    return nullptr;
+  }
+
+  RefPtr<SessionStoreParent::FlushTabStatePromise> promise =
+      SendFlushTabState();
+  return promise.forget();
+}
+
+void SessionStoreParent::FinalFlushAllSessionStoreChildren(
+    const std::function<void()>& aDone) {
+  if (!mBrowsingContext) {
+    aDone();
+    return;
+  }
+
+  SessionStoreChild* sessionStoreChild =
+      static_cast<SessionStoreChild*>(InProcessParent::ChildActorFor(this));
+  if (!sessionStoreChild || mozilla::SessionHistoryInParent()) {
+    return FlushAllSessionStoreChildren(aDone);
+  }
+
+  sessionStoreChild->FlushSessionStore();
+  mBrowsingContext->UpdateSessionStoreSessionStorage(aDone);
+}
+
+mozilla::ipc::IPCResult SessionStoreParent::RecvSessionStoreUpdate(
+    const Maybe<nsCString>& aDocShellCaps, const Maybe<bool>& aPrivatedMode,
+    const bool aNeedCollectSHistory, const uint32_t& aEpoch) {
+  if (!mBrowsingContext) {
+    return IPC_OK();
+  }
+
+  SessionStoreUpdate(mBrowsingContext, aDocShellCaps, aPrivatedMode,
+                     aNeedCollectSHistory, aEpoch);
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult SessionStoreParent::RecvIncrementalSessionStoreUpdate(
+    const MaybeDiscarded<BrowsingContext>& aBrowsingContext,
+    const Maybe<FormData>& aFormData, const Maybe<nsPoint>& aScrollPosition,
+    uint32_t aEpoch) {
+  if (!aBrowsingContext.IsNull()) {
+    mSessionStore->UpdateSessionStore(
+        aBrowsingContext.GetMaybeDiscarded()->Canonical(), aFormData,
+        aScrollPosition, aEpoch);
+  }
+
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult SessionStoreParent::RecvResetSessionStore(
+    const MaybeDiscarded<BrowsingContext>& aBrowsingContext, uint32_t aEpoch) {
+  if (!aBrowsingContext.IsNull()) {
+    mSessionStore->RemoveSessionStore(
+        aBrowsingContext.GetMaybeDiscarded()->Canonical());
+  }
+  return IPC_OK();
+}
+
+NS_IMPL_CYCLE_COLLECTION(SessionStoreParent, mBrowsingContext, mSessionStore)
+NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(SessionStoreParent, AddRef)
+NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(SessionStoreParent, Release)

toolkit/components/sessionstore/SessionStoreParent.h

@@ -0,0 +1,58 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_dom_SessionStoreParent_h
+#define mozilla_dom_SessionStoreParent_h
+
+#include "mozilla/dom/BrowserSessionStore.h"
+#include "mozilla/dom/CanonicalBrowsingContext.h"
+#include "mozilla/dom/Element.h"
+#include "mozilla/dom/PSessionStoreParent.h"
+#include "mozilla/dom/WindowGlobalParent.h"
+
+namespace mozilla::dom {
+class BrowserParent;
+
+class SessionStoreParent final : public PSessionStoreParent {
+ public:
+  SessionStoreParent(CanonicalBrowsingContext* aBrowsingContext,
+                     BrowserSessionStore* aSessionStore);
+
+  void FlushAllSessionStoreChildren(const std::function<void()>& aDone);
+
+  void FinalFlushAllSessionStoreChildren(const std::function<void()>& aDone);
+
+  /**
+   * Sends data to be stored and instructions to the session store to
+   * potentially collect data in the parent.
+   */
+  mozilla::ipc::IPCResult RecvSessionStoreUpdate(
+      const Maybe<nsCString>& aDocShellCaps, const Maybe<bool>& aPrivatedMode,
+      const bool aNeedCollectSHistory, const uint32_t& aEpoch);
+
+  mozilla::ipc::IPCResult RecvIncrementalSessionStoreUpdate(
+      const MaybeDiscarded<BrowsingContext>& aBrowsingContext,
+      const Maybe<FormData>& aFormData, const Maybe<nsPoint>& aScrollPosition,
+      uint32_t aEpoch);
+
+  mozilla::ipc::IPCResult RecvResetSessionStore(
+      const MaybeDiscarded<BrowsingContext>& aBrowsingContext, uint32_t aEpoch);
+
+  NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(SessionStoreParent)
+  NS_DECL_CYCLE_COLLECTION_NATIVE_CLASS(SessionStoreParent)
+
+ private:
+  ~SessionStoreParent() = default;
+
+  already_AddRefed<SessionStoreParent::FlushTabStatePromise>
+  FlushSessionStore();
+
+  RefPtr<CanonicalBrowsingContext> mBrowsingContext;
+  RefPtr<BrowserSessionStore> mSessionStore;
+};
+}  // namespace mozilla::dom
+
+#endif  // mozilla_dom_SessionStoreParent_h

toolkit/components/sessionstore/SessionStoreScrollData.cpp

@@ -0,0 +1,123 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/dom/SessionStoreScrollData.h"
+#include <utility>
+
+#include "js/PropertyAndElement.h"
+#include "js/TypeDecls.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/dom/BindingUtils.h"
+#include "mozilla/dom/BrowserSessionStoreBinding.h"
+#include "mozilla/dom/BrowsingContext.h"
+
+#include "nsPresContext.h"
+
+#include "mozilla/dom/WebIDLGlobalNameHash.h"
+#include "js/PropertyDescriptor.h"
+
+#include "mozilla/dom/ToJSValue.h"
+#include "mozilla/dom/GeneratedAtomList.h"
+#include "js/StructuredClone.h"
+#include "mozilla/dom/DOMJSClass.h"
+#include "mozilla/dom/StructuredCloneHolder.h"
+#include "nsContentUtils.h"
+#include "js/Array.h"
+#include "js/JSON.h"
+
+using namespace mozilla::dom;
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(SessionStoreScrollData)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(SessionStoreScrollData)
+
+NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_WEAK_PTR(SessionStoreScrollData,
+                                               mChildren)
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(SessionStoreScrollData)
+  NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
+  NS_INTERFACE_MAP_ENTRY(nsISupports)
+NS_INTERFACE_MAP_END
+
+nsISupports* SessionStoreScrollData::GetParentObject() const {
+  return xpc::NativeGlobal(xpc::PrivilegedJunkScope());
+  ;
+}
+
+JSObject* SessionStoreScrollData::WrapObject(
+    JSContext* aCx, JS::Handle<JSObject*> aGivenProto) {
+  return SessionStoreScrollData_Binding::Wrap(aCx, this, aGivenProto);
+}
+
+void SessionStoreScrollData::GetScroll(nsACString& aScroll) const {
+  int scrollX = nsPresContext::AppUnitsToIntCSSPixels(mScroll.x);
+  int scrollY = nsPresContext::AppUnitsToIntCSSPixels(mScroll.y);
+
+  if ((scrollX != 0) || (scrollY != 0)) {
+    aScroll = nsPrintfCString("%d,%d", scrollX, scrollY);
+  } else {
+    aScroll.SetIsVoid(true);
+  }
+}
+
+SessionStoreScrollData::ChildrenArray& SessionStoreScrollData::Children() {
+  return mChildren;
+}
+
+void SessionStoreScrollData::GetChildren(
+    Nullable<ChildrenArray>& aChildren) const {
+  if (!mChildren.IsEmpty()) {
+    aChildren.SetValue() = mChildren.Clone();
+  } else {
+    aChildren.SetNull();
+  }
+}
+
+void SessionStoreScrollData::ToJSON(JSContext* aCx,
+                                    JS::MutableHandleObject aRetval) {
+  JS::RootedObject self(aCx);
+  {
+    JS::RootedValue value(aCx);
+    if (!GetOrCreateDOMReflector(aCx, this, &value)) {
+      return;
+    }
+
+    self.set(value.toObjectOrNull());
+  }
+
+  JS::RootedObject result(aCx, JS_NewPlainObject(aCx));
+
+  if (!IsEmpty()) {
+    if (HasData(mScroll)) {
+      if (!SessionStoreUtils::CopyProperty(aCx, result, self, u"scroll"_ns)) {
+        return;
+      }
+    }
+
+    SessionStoreUtils::CopyChildren(aCx, result, mChildren);
+  }
+
+  aRetval.set(result);
+}
+
+void SessionStoreScrollData::Update(const CollectedType& aUpdate) {
+  SessionStoreScrollData_Binding::ClearCachedScrollValue(this);
+  mScroll = aUpdate;
+}
+
+void SessionStoreScrollData::ClearCachedChildren() {
+  SessionStoreScrollData_Binding::ClearCachedChildrenValue(this);
+}
+
+/* static */
+bool SessionStoreScrollData::HasData(const CollectedType& aPoint) {
+  int scrollX = nsPresContext::AppUnitsToIntCSSPixels(aPoint.x);
+  int scrollY = nsPresContext::AppUnitsToIntCSSPixels(aPoint.y);
+  return scrollX != 0 || scrollY != 0;
+}
+
+bool SessionStoreScrollData::IsEmpty() const {
+  return !HasData(mScroll) && mChildren.IsEmpty();
+}

toolkit/components/sessionstore/SessionStoreScrollData.h

@@ -0,0 +1,61 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_dom_SessionStoreScrollData_h
+#define mozilla_dom_SessionStoreScrollData_h
+
+#include "mozilla/WeakPtr.h"
+#include "nsPoint.h"
+#include "nsTArray.h"
+#include "nsWrapperCache.h"
+#include "mozilla/dom/WindowGlobalParent.h"
+
+namespace mozilla::dom {
+
+class BrowsingContext;
+class WindowGlobalParent;
+class OwningByteStringOrObjectOrNull;
+
+class SessionStoreScrollData final : public nsISupports,
+                                     public nsWrapperCache,
+                                     public SupportsWeakPtr {
+ public:
+  using CollectedType = nsPoint;
+  using LocationType = WeakPtr<SessionStoreScrollData>;
+  using ChildrenArray = nsTArray<RefPtr<SessionStoreScrollData>>;
+
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(SessionStoreScrollData)
+  nsISupports* GetParentObject() const;
+  JSObject* WrapObject(JSContext* aCx,
+                       JS::Handle<JSObject*> aGivenProto) override;
+
+  void GetScroll(nsACString& aScroll) const;
+
+  ChildrenArray& Children();
+
+  void GetChildren(Nullable<ChildrenArray>& aChildren) const;
+
+  void ToJSON(JSContext* aCx, JS::MutableHandleObject aRetval);
+
+  void Update(const CollectedType& aUpdate);
+
+  void ClearCachedChildren();
+
+  static bool HasData(const CollectedType& aPoint);
+
+  bool IsEmpty() const;
+
+ private:
+  ~SessionStoreScrollData() = default;
+
+  nsPoint mScroll;
+  nsTArray<RefPtr<SessionStoreScrollData>> mChildren;
+};
+
+}  // namespace mozilla::dom
+
+#endif  // mozilla_dom_SessionStoreScrollData_h

toolkit/components/sessionstore/SessionStoreTypes.ipdlh

@@ -52,6 +52,7 @@ struct FormData {
   FormEntry[] id;
   FormEntry[] xpath;
   nsString innerHTML;
+  nsCString uri;
 };
 
 struct DocShellRestoreState {

toolkit/components/sessionstore/SessionStoreUtils.cpp

@@ -7,6 +7,7 @@
 #include "js/Array.h"  // JS::GetArrayLength, JS::IsArrayObject
 #include "js/JSON.h"
 #include "js/PropertyAndElement.h"  // JS_GetElement
+#include "js/TypeDecls.h"
 #include "jsapi.h"
 #include "mozilla/PresShell.h"
 #include "mozilla/dom/AutocompleteInfoBinding.h"
@@ -19,6 +20,8 @@
 #include "mozilla/dom/RootedDictionary.h"
 #include "mozilla/dom/SessionStorageManager.h"
 #include "mozilla/dom/PBackgroundSessionStorageCache.h"
+#include "mozilla/dom/SessionStoreChangeListener.h"
+#include "mozilla/dom/SessionStoreChild.h"
 #include "mozilla/dom/SessionStoreUtils.h"
 #include "mozilla/dom/txIXPathContext.h"
 #include "mozilla/dom/WindowGlobalParent.h"
@@ -300,6 +303,10 @@ void SessionStoreUtils::RestoreScrollPosition(const GlobalObject& aGlobal,
 /* static */
 void SessionStoreUtils::RestoreScrollPosition(
     nsGlobalWindowInner& aWindow, const nsCString& aScrollPosition) {
+  using Change = mozilla::dom::SessionStoreChangeListener::Change;
+  SessionStoreChangeListener::CollectSessionStoreData(
+      aWindow.GetWindowContext(), EnumSet<Change>(Change::Scroll));
+
   nsCCharSeparatedTokenizer tokenizer(aScrollPosition, ',');
   nsAutoCString token(tokenizer.nextToken());
   int pos_X = atoi(token.get());
@@ -1203,6 +1210,7 @@ bool SessionStoreUtils::RestoreFormData(const GlobalObject& aGlobal,
   if (!aData.mUrl.WasPassed()) {
     return true;
   }
+
   // Don't restore any data for the given frame if the URL
   // stored in the form data doesn't match its current URL.
   nsAutoCString url;
@@ -1210,6 +1218,11 @@ bool SessionStoreUtils::RestoreFormData(const GlobalObject& aGlobal,
   if (!aData.mUrl.Value().Equals(url)) {
     return false;
   }
+
+  using Change = SessionStoreChangeListener::Change;
+  SessionStoreChangeListener::CollectSessionStoreData(
+      aDocument.GetWindowContext(), EnumSet<Change>(Change::Input));
+
   if (aData.mInnerHTML.WasPassed()) {
     SetInnerHTML(aDocument, aData.mInnerHTML.Value());
   }
@@ -1311,6 +1324,10 @@ void RestoreFormEntry(Element* aNode, const FormEntryValue& aValue) {
 void SessionStoreUtils::RestoreFormData(
     Document& aDocument, const nsString& aInnerHTML,
     const nsTArray<SessionStoreRestoreData::Entry>& aEntries) {
+  using Change = SessionStoreChangeListener::Change;
+  SessionStoreChangeListener::CollectSessionStoreData(
+      aDocument.GetWindowContext(), EnumSet<Change>(Change::Input));
+
   if (!aInnerHTML.IsEmpty()) {
     SetInnerHTML(aDocument, aInnerHTML);
   }
@@ -1698,20 +1715,31 @@ nsresult SessionStoreUtils::ConstructSessionStorageValues(
   return NS_OK;
 }
 
-/* static */ void SessionStoreUtils::ResetSessionStore(
+/* static */
-    BrowsingContext* aContext) {
+bool SessionStoreUtils::CopyProperty(JSContext* aCx, JS::HandleObject aDst,
-  MOZ_RELEASE_ASSERT(NATIVE_LISTENER);
+                                     JS::HandleObject aSrc,
-  WindowContext* windowContext = aContext->GetCurrentWindowContext();
+                                     const nsAString& aName) {
-  if (!windowContext) {
+  JS::RootedId name(aCx);
-    return;
+  const char16_t* data;
+  size_t length = aName.GetData(&data);
+
+  if (!JS_CharsToId(aCx, JS::TwoByteChars(data, length), &name)) {
+    return false;
   }
 
-  WindowGlobalChild* windowChild = windowContext->GetWindowGlobalChild();
+  bool found = false;
-  if (!windowChild || !windowChild->CanSend()) {
+  if (!JS_HasPropertyById(aCx, aSrc, name, &found) || !found) {
-    return;
+    return true;
   }
 
-  uint32_t epoch = aContext->GetSessionStoreEpoch();
+  JS::RootedValue value(aCx);
+  if (!JS_GetPropertyById(aCx, aSrc, name, &value)) {
+    return false;
+  }
 
-  Unused << windowChild->SendResetSessionStore(epoch);
+  if (value.isNullOrUndefined()) {
+    return true;
+  }
+
+  return JS_DefinePropertyById(aCx, aDst, name, value, JSPROP_ENUMERATE);
 }

toolkit/components/sessionstore/SessionStoreUtils.h

@@ -8,6 +8,7 @@
 #define mozilla_dom_SessionStoreUtils_h
 
 #include "mozilla/Attributes.h"
+#include "mozilla/IntegerRange.h"
 #include "mozilla/dom/BindingDeclarations.h"
 #include "mozilla/dom/CanonicalBrowsingContext.h"
 #include "mozilla/dom/SessionStoreUtilsBinding.h"
@@ -139,14 +140,44 @@ class SessionStoreUtils {
       const nsTArray<SSCacheCopy>& aValues,
       Record<nsCString, Record<nsString, nsString>>& aStorage);
 
-  static void ResetSessionStore(BrowsingContext* aContext);
-
 #if defined(MOZ_WIDGET_ANDROID) || defined(MOZ_THUNDERBIRD) || \
     defined(MOZ_SUITE)
   static constexpr bool NATIVE_LISTENER = false;
 #else
   static constexpr bool NATIVE_LISTENER = true;
 #endif
+
+  static bool CopyProperty(JSContext* aCx, JS::HandleObject aDst,
+                           JS::HandleObject aSrc, const nsAString& aName);
+
+  template <typename T>
+  static bool CopyChildren(JSContext* aCx, JS::HandleObject aDst,
+                           const nsTArray<RefPtr<T>>& aChildren) {
+    if (!aChildren.IsEmpty()) {
+      JS::RootedObject children(aCx,
+                                JS::NewArrayObject(aCx, aChildren.Length()));
+
+      for (const auto index : IntegerRange(aChildren.Length())) {
+        if (!aChildren[index]) {
+          continue;
+        }
+
+        JS::RootedObject object(aCx);
+        aChildren[index]->ToJSON(aCx, &object);
+
+        if (!JS_DefineElement(aCx, children, index, object, JSPROP_ENUMERATE)) {
+          return false;
+        }
+      }
+
+      if (!JS_DefineProperty(aCx, aDst, "children", children,
+                             JSPROP_ENUMERATE)) {
+        return false;
+      }
+    }
+
+    return true;
+  }
 };
 
 }  // namespace dom

toolkit/components/sessionstore/moz.build

@@ -5,21 +5,29 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 EXPORTS.mozilla.dom += [
+    "BrowserSessionStore.h",
     "SessionStoreChangeListener.h",
+    "SessionStoreChild.h",
     "SessionStoreData.h",
-    "SessionStoreDataCollector.h",
+    "SessionStoreFormData.h",
     "SessionStoreListener.h",
     "SessionStoreMessageUtils.h",
+    "SessionStoreParent.h",
     "SessionStoreRestoreData.h",
+    "SessionStoreScrollData.h",
     "SessionStoreUtils.h",
 ]
 
 UNIFIED_SOURCES += [
+    "BrowserSessionStore.cpp",
     "RestoreTabContentObserver.cpp",
     "SessionStoreChangeListener.cpp",
-    "SessionStoreDataCollector.cpp",
+    "SessionStoreChild.cpp",
+    "SessionStoreFormData.cpp",
     "SessionStoreListener.cpp",
+    "SessionStoreParent.cpp",
     "SessionStoreRestoreData.cpp",
+    "SessionStoreScrollData.cpp",
     "SessionStoreUtils.cpp",
 ]
 
@@ -35,6 +43,7 @@ XPIDL_SOURCES += [
 ]
 
 IPDL_SOURCES += [
+    "PSessionStore.ipdl",
     "SessionStoreTypes.ipdlh",
 ]