Bug 1667449 - Hide fission.sessionHistoryInParent pref getter behind a function r=peterv

Differential Revision: https://phabricator.services.mozilla.com/D91462
2020-09-28 12:01:12 +00:00
parent 5e1d0cbcd2
commit 517a59e62b
50 changed files with 169 additions and 212 deletions
--- a/docshell/base/nsDocShell.cpp
+++ b/docshell/base/nsDocShell.cpp
@@ -163,6 +163,7 @@
 #include "nsIWindowWatcher.h"
 #include "nsIWritablePropertyBag2.h"
 #include "nsIX509Cert.h"
+#include "nsIXULRuntime.h"

 #include "nsCommandManager.h"
 #include "nsPIDOMWindow.h"
@@ -830,7 +831,7 @@ nsresult nsDocShell::LoadURI(nsDocShellLoadState* aLoadState,
    MOZ_LOG(gSHLog, LogLevel::Debug,
            ("nsDocShell[%p]: loading from session history", this));

-    if (!StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+    if (!mozilla::SessionHistoryInParent()) {
      return LoadHistoryEntry(aLoadState->SHEntry(), aLoadState->LoadType());
    }

@@ -925,7 +926,7 @@ bool nsDocShell::MaybeHandleSubframeHistory(
  parentDS->GetLoadType(&parentLoadType);

  if (!aContinueHandlingSubframeHistory) {
-    if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+    if (mozilla::SessionHistoryInParent()) {
      if (nsDocShell::Cast(parentDS.get())->IsLoadingFromSessionHistory() &&
          !GetCreatedDynamically()) {
        if (XRE_IsContentProcess()) {
@@ -1146,7 +1147,7 @@ void nsDocShell::FirePageHideNotificationInternal(
        MOZ_LOG(
            gSHLog, LogLevel::Debug,
            ("nsDocShell %p unloading, remove dynamic subframe entries", this));
-        if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+        if (mozilla::SessionHistoryInParent()) {
          if (mActiveEntry) {
            mBrowsingContext->RemoveDynEntriesFromActiveSessionHistoryEntry();
          }
@@ -1404,7 +1405,7 @@ bool nsDocShell::SetCurrentURI(nsIURI* aURI, nsIRequest* aRequest,
  bool isRoot = mBrowsingContext->IsTop();
  bool isSubFrame = false;  // Is this a subframe navigation?

-  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+  if (mozilla::SessionHistoryInParent()) {
    if (mLoadingEntry) {
      isSubFrame = mLoadingEntry->mInfo.IsSubFrame();
      MOZ_LOG(gSHLog, LogLevel::Debug,
@@ -2720,7 +2721,7 @@ void nsDocShell::StoreWindowNameToSHEntries() {
        mOSHE, [&](nsISHEntry* aEntry) { aEntry->SetName(name); });
  }

-  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+  if (mozilla::SessionHistoryInParent()) {
    if (XRE_IsParentProcess()) {
      SessionHistoryEntry* entry =
          mBrowsingContext->Canonical()->GetActiveSessionHistoryEntry();
@@ -3051,7 +3052,7 @@ nsresult nsDocShell::AddChildSHEntry(nsISHEntry* aCloneRef,
                                     nsISHEntry* aNewEntry,
                                     int32_t aChildOffset, uint32_t aLoadType,
                                     bool aCloneChildren) {
-  MOZ_ASSERT(!StaticPrefs::fission_sessionHistoryInParent_AtStartup());
+  MOZ_ASSERT(!mozilla::SessionHistoryInParent());
  nsresult rv = NS_OK;

  if (mLSHE && aLoadType != LOAD_PUSHSTATE) {
@@ -3079,7 +3080,7 @@ nsresult nsDocShell::AddChildSHEntry(nsISHEntry* aCloneRef,
 nsresult nsDocShell::AddChildSHEntryToParent(nsISHEntry* aNewEntry,
                                             int32_t aChildOffset,
                                             bool aCloneChildren) {
-  MOZ_ASSERT(!StaticPrefs::fission_sessionHistoryInParent_AtStartup());
+  MOZ_ASSERT(!mozilla::SessionHistoryInParent());
  /* You will get here when you are in a subframe and
   * a new url has been loaded on you.
   * The mOSHE in this subframe will be the previous url's
@@ -3240,7 +3241,7 @@ nsDocShell::GetDeviceSizeIsPageSize(bool* aValue) {
 }

 void nsDocShell::ClearFrameHistory(nsISHEntry* aEntry) {
-  MOZ_ASSERT(!StaticPrefs::fission_sessionHistoryInParent_AtStartup());
+  MOZ_ASSERT(!mozilla::SessionHistoryInParent());
  RefPtr<ChildSHistory> rootSH = GetRootSessionHistory();
  if (!rootSH || !aEntry) {
    return;
@@ -3982,7 +3983,7 @@ nsresult nsDocShell::LoadErrorPage(nsIURI* aErrorURI, nsIURI* aFailedURI,
    // identifier, the error page won't persist.
    mLSHE->AbandonBFCacheEntry();
  }
-  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+  if (mozilla::SessionHistoryInParent()) {
    // Commit the loading entry for the real load here, Embed will not commit
    // the loading entry for the error page. History will then contain an entry
    // for the real load, and the error page won't persist if we try loading
@@ -4018,7 +4019,7 @@ nsDocShell::Reload(uint32_t aReloadFlags) {
  // Send notifications to the HistoryListener if any, about the impending
  // reload
  RefPtr<ChildSHistory> rootSH = GetRootSessionHistory();
-  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+  if (mozilla::SessionHistoryInParent()) {
    MOZ_LOG(gSHLog, LogLevel::Debug, ("nsDocShell %p Reload", this));
    bool forceReload = IsForceReloadType(loadType);
    if (!XRE_IsParentProcess()) {
@@ -4284,7 +4285,7 @@ nsDocShell::LoadPageAsViewSource(nsIDocShell* aOtherDocShell,
  RefPtr<nsDocShellLoadState> loadState;
  uint32_t cacheKey;
  auto* otherDocShell = nsDocShell::Cast(aOtherDocShell);
-  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+  if (mozilla::SessionHistoryInParent()) {
    loadState = new nsDocShellLoadState(newURI);
    if (!otherDocShell->FillLoadStateFromCurrentEntry(*loadState)) {
      return NS_ERROR_INVALID_POINTER;
@@ -4342,7 +4343,7 @@ nsDocShell::GetCurrentDescriptor(nsISupports** aPageDescriptor) {
 already_AddRefed<nsIInputStream> nsDocShell::GetPostDataFromCurrentEntry()
    const {
  nsCOMPtr<nsIInputStream> postData;
-  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+  if (mozilla::SessionHistoryInParent()) {
    if (mActiveEntry) {
      postData = mActiveEntry->GetPostData();
    } else if (mLoadingEntry) {
@@ -4360,7 +4361,7 @@ already_AddRefed<nsIInputStream> nsDocShell::GetPostDataFromCurrentEntry()
 }

 Maybe<uint32_t> nsDocShell::GetCacheKeyFromCurrentEntry() const {
-  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+  if (mozilla::SessionHistoryInParent()) {
    if (mActiveEntry) {
      return Some(mActiveEntry->GetCacheKey());
    }
@@ -5683,8 +5684,7 @@ nsresult nsDocShell::Embed(nsIContentViewer* aContentViewer,
  NS_ENSURE_SUCCESS(rv, rv);

  // XXX What if SetupNewViewer fails?
-  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup() ? !!mLoadingEntry
-                                                              : !!mLSHE) {
+  if (mozilla::SessionHistoryInParent() ? !!mLoadingEntry : !!mLSHE) {
    // Set history.state
    SetDocCurrentStateObj(mLSHE,
                          mLoadingEntry ? &mLoadingEntry->mInfo : nullptr);
@@ -5699,8 +5699,7 @@ nsresult nsDocShell::Embed(nsIContentViewer* aContentViewer,
    SetHistoryEntryAndUpdateBC(Nothing(), Some<nsISHEntry*>(mLSHE));
  }

-  if (!aIsTransientAboutBlank &&
-      StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+  if (!aIsTransientAboutBlank && mozilla::SessionHistoryInParent()) {
    MOZ_LOG(gSHLog, LogLevel::Debug, ("document %p Embed", this));
    MoveLoadingToActiveEntry(mLoadType != LOAD_ERROR_PAGE);
  }
@@ -7003,7 +7002,7 @@ nsresult nsDocShell::CaptureState() {
  if (MOZ_UNLIKELY(MOZ_LOG_TEST(gPageCacheLog, LogLevel::Debug))) {
    nsAutoCString spec;
    nsCOMPtr<nsIURI> uri;
-    if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+    if (mozilla::SessionHistoryInParent()) {
      uri = mActiveEntry->GetURI();
    } else {
      uri = mOSHE->GetURI();
@@ -7325,7 +7324,7 @@ nsresult nsDocShell::RestoreFromHistory() {
  RefPtr<ChildSHistory> rootSH = GetRootSessionHistory();
  if (rootSH) {
    mPreviousEntryIndex = rootSH->Index();
-    if (!StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+    if (!mozilla::SessionHistoryInParent()) {
      rootSH->LegacySHistory()->UpdateIndex();
    }
    mLoadedEntryIndex = rootSH->Index();
@@ -7854,8 +7853,7 @@ nsresult nsDocShell::CreateContentViewer(const nsACString& aContentType,
    // Be sure to have a correct mLSHE, it may have been cleared by
    // EndPageLoad. See bug 302115.
    ChildSHistory* shistory = GetSessionHistory();
-    if (!StaticPrefs::fission_sessionHistoryInParent_AtStartup() && shistory &&
-        !mLSHE) {
+    if (!mozilla::SessionHistoryInParent() && shistory && !mLSHE) {
      int32_t idx = shistory->LegacySHistory()->GetRequestedIndex();
      if (idx == -1) {
        idx = shistory->Index();
@@ -8195,7 +8193,7 @@ void nsDocShell::SetDocCurrentStateObj(nsISHEntry* aShEntry,
  NS_ENSURE_TRUE_VOID(document);

  nsCOMPtr<nsIStructuredCloneContainer> scContainer;
-  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+  if (mozilla::SessionHistoryInParent()) {
    // If aInfo is null, just set the document's state object to null.
    if (aInfo) {
      scContainer = aInfo->GetStateData();
@@ -8623,7 +8621,7 @@ bool nsDocShell::IsSameDocumentNavigation(nsDocShellLoadState* aLoadState,
    }
  }

-  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+  if (mozilla::SessionHistoryInParent()) {
    if (mActiveEntry && aLoadState->LoadIsFromSessionHistory()) {
      aState.mHistoryNavBetweenSameDoc = mActiveEntry->SharesDocumentWith(
          aLoadState->GetLoadingSessionHistoryInfo()->mInfo);
@@ -8643,7 +8641,7 @@ bool nsDocShell::IsSameDocumentNavigation(nsDocShellLoadState* aLoadState,
 #ifdef DEBUG
  if (aState.mHistoryNavBetweenSameDoc) {
    nsCOMPtr<nsIInputStream> currentPostData;
-    if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+    if (mozilla::SessionHistoryInParent()) {
      currentPostData = mActiveEntry->GetPostData();
    } else {
      currentPostData = mOSHE->GetPostData();
@@ -8667,7 +8665,7 @@ bool nsDocShell::IsSameDocumentNavigation(nsDocShellLoadState* aLoadState,
  // The restriction that the SHEntries in (a) must be different ensures
  // that history.go(0) and the like trigger full refreshes, rather than
  // same document navigations.
-  if (!StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+  if (!mozilla::SessionHistoryInParent()) {
    bool doSameDocumentNavigation =
        (aState.mHistoryNavBetweenSameDoc && mOSHE != aLoadState->SHEntry()) ||
        (!aLoadState->SHEntry() && !aLoadState->PostDataStream() &&
@@ -8744,9 +8742,8 @@ nsresult nsDocShell::HandleSameDocumentNavigation(
  nsCOMPtr<nsIPrincipal> newURITriggeringPrincipal, newURIPrincipalToInherit,
      newURIPartitionedPrincipalToInherit;
  nsCOMPtr<nsIContentSecurityPolicy> newCsp;
-  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup() ? !!mActiveEntry
-                                                              : !!mOSHE) {
-    if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+  if (mozilla::SessionHistoryInParent() ? !!mActiveEntry : !!mOSHE) {
+    if (mozilla::SessionHistoryInParent()) {
      newURITriggeringPrincipal = mActiveEntry->GetTriggeringPrincipal();
      newURIPrincipalToInherit = mActiveEntry->GetPrincipalToInherit();
      newURIPartitionedPrincipalToInherit =
@@ -8781,9 +8778,8 @@ nsresult nsDocShell::HandleSameDocumentNavigation(
  uint32_t cacheKey = 0;

  bool scrollRestorationIsManual = false;
-  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup() ? !!mActiveEntry
-                                                              : !!mOSHE) {
-    if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+  if (mozilla::SessionHistoryInParent() ? !!mActiveEntry : !!mOSHE) {
+    if (mozilla::SessionHistoryInParent()) {
      // FIXME Need to set scroll position on mActiveEntry.
      scrollRestorationIsManual = mActiveEntry->GetScrollRestorationIsManual();
    } else {
@@ -8798,7 +8794,7 @@ nsresult nsDocShell::HandleSameDocumentNavigation(
    // above -- it filters out some LOAD_CMD_NORMAL cases that we
    // wouldn't want here.
    if (aLoadState->LoadType() & LOAD_CMD_NORMAL) {
-      if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+      if (mozilla::SessionHistoryInParent()) {
        postData = mActiveEntry->GetPostData();
        cacheKey = mActiveEntry->GetCacheKey();
      } else {
@@ -8831,7 +8827,7 @@ nsresult nsDocShell::HandleSameDocumentNavigation(

  // If we're doing a history load, use its scroll restoration state.
  if (aLoadState->LoadIsFromSessionHistory()) {
-    if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+    if (mozilla::SessionHistoryInParent()) {
      scrollRestorationIsManual = aLoadState->GetLoadingSessionHistoryInfo()
                                      ->mInfo.GetScrollRestorationIsManual();
    } else {
@@ -8862,8 +8858,7 @@ nsresult nsDocShell::HandleSameDocumentNavigation(
      SetCacheKeyOnHistoryEntry(mOSHE, cacheKey);
    }
  }
-  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup() &&
-      mLoadingEntry) {
+  if (mozilla::SessionHistoryInParent() && mLoadingEntry) {
    MOZ_LOG(
        gSHLog, LogLevel::Debug,
        ("Moving the loading entry to the active entry on nsDocShell %p to %s",
@@ -8933,13 +8928,12 @@ nsresult nsDocShell::HandleSameDocumentNavigation(
  nscoord bx = 0;
  nscoord by = 0;
  bool needsScrollPosUpdate = false;
-  if ((StaticPrefs::fission_sessionHistoryInParent_AtStartup() ? !!mActiveEntry
-                                                               : !!mOSHE) &&
+  if ((mozilla::SessionHistoryInParent() ? !!mActiveEntry : !!mOSHE) &&
      (aLoadState->LoadType() == LOAD_HISTORY ||
       aLoadState->LoadType() == LOAD_RELOAD_NORMAL) &&
      !scrollRestorationIsManual) {
    needsScrollPosUpdate = true;
-    if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+    if (mozilla::SessionHistoryInParent()) {
      mActiveEntry->GetScrollPosition(&bx, &by);
    } else {
      mOSHE->GetScrollPosition(&bx, &by);
@@ -9257,7 +9251,7 @@ nsresult nsDocShell::InternalLoad(nsDocShellLoadState* aLoadState,
    SetHistoryEntryAndUpdateBC(Some<nsISHEntry*>(aLoadState->SHEntry()),
                               Nothing());
    if (aLoadState->LoadIsFromSessionHistory() &&
-        !StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+        !mozilla::SessionHistoryInParent()) {
      // We're making history navigation or a reload. Make sure our history ID
      // points to the same ID as SHEntry's docshell ID.
      nsID historyID = {};
@@ -9283,7 +9277,7 @@ nsresult nsDocShell::InternalLoad(nsDocShellLoadState* aLoadState,
    if (shistory) {
      shistory->RemovePendingHistoryNavigations();
    }
-    if (!StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+    if (!mozilla::SessionHistoryInParent()) {
      // It's possible that the previous viewer of mContentViewer is the
      // viewer that will end up in aLoadState->SHEntry() when it gets closed.
      // If that's the case, we need to go ahead and force it into its shentry
@@ -10085,7 +10079,7 @@ nsresult nsDocShell::DoURILoad(nsDocShellLoadState* aLoadState,
  uint32_t cacheKey = 0;
  if (aCacheKey) {
    cacheKey = *aCacheKey;
-  } else if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+  } else if (mozilla::SessionHistoryInParent()) {
    if (mLoadingEntry) {
      cacheKey = mLoadingEntry->mInfo.GetCacheKey();
    } else if (mActiveEntry) {  // for reload cases
@@ -10656,8 +10650,7 @@ bool nsDocShell::OnNewURI(nsIURI* aURI, nsIChannel* aChannel,
   * Hopefully I don't have to do that.
   */
  if (equalUri &&
-      (StaticPrefs::fission_sessionHistoryInParent_AtStartup() ? !!mActiveEntry
-                                                               : !!mOSHE) &&
+      (mozilla::SessionHistoryInParent() ? !!mActiveEntry : !!mOSHE) &&
      (mLoadType == LOAD_NORMAL || mLoadType == LOAD_LINK ||
       mLoadType == LOAD_STOP_CONTENT) &&
      !inputStream) {
@@ -10691,14 +10684,14 @@ bool nsDocShell::OnNewURI(nsIURI* aURI, nsIChannel* aChannel,

    SetCacheKeyOnHistoryEntry(mLSHE ? mLSHE : mOSHE, cacheKey);

-    if (!StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+    if (!mozilla::SessionHistoryInParent()) {
      // Since we're force-reloading, clear all the sub frame history.
      ClearFrameHistory(mLSHE);
      ClearFrameHistory(mOSHE);
    }
  }

-  if (!StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+  if (!mozilla::SessionHistoryInParent()) {
    // Clear subframe history on refresh.
    // XXX: history.go(0) won't go this path as aLoadType is LOAD_HISTORY in
    // this case. One should re-validate after bug 1331865 fixed.
@@ -10748,11 +10741,11 @@ bool nsDocShell::OnNewURI(nsIURI* aURI, nsIChannel* aChannel,
  // If this was a history load or a refresh, or it was a history load but
  // later changed to LOAD_NORMAL_REPLACE due to redirection, update the index
  // in session history.
-  if (!StaticPrefs::fission_sessionHistoryInParent_AtStartup() && rootSH &&
+  if (!mozilla::SessionHistoryInParent() && rootSH &&
      ((mLoadType & (LOAD_CMD_HISTORY | LOAD_CMD_RELOAD)) ||
       mLoadType == LOAD_NORMAL_REPLACE)) {
    mPreviousEntryIndex = rootSH->Index();
-    if (!StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+    if (!mozilla::SessionHistoryInParent()) {
      rootSH->LegacySHistory()->UpdateIndex();
    }
    mLoadedEntryIndex = rootSH->Index();
@@ -10998,7 +10991,7 @@ nsresult nsDocShell::UpdateURLAndHistory(Document* aDocument, nsIURI* aNewURI,
  aNewURI->EqualsExceptRef(aCurrentURI, &sameExceptHashes);
  bool uriWasModified;
  if (sameExceptHashes) {
-    if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+    if (mozilla::SessionHistoryInParent()) {
      uriWasModified = mActiveEntry && mActiveEntry->GetURIWasModified();
    } else {
      uriWasModified = oldOSHE && oldOSHE->GetURIWasModified();
@@ -11023,7 +11016,7 @@ nsresult nsDocShell::UpdateURLAndHistory(Document* aDocument, nsIURI* aNewURI,
    nsPoint scrollPos = GetCurScrollPos();

    bool scrollRestorationIsManual;
-    if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+    if (mozilla::SessionHistoryInParent()) {
      // FIXME Need to save the current scroll position on mActiveEntry.
      scrollRestorationIsManual = mActiveEntry->GetScrollRestorationIsManual();
    } else {
@@ -11035,7 +11028,7 @@ nsresult nsDocShell::UpdateURLAndHistory(Document* aDocument, nsIURI* aNewURI,

    nsCOMPtr<nsIContentSecurityPolicy> csp = aDocument->GetCsp();

-    if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+    if (mozilla::SessionHistoryInParent()) {
      MOZ_LOG(gSHLog, LogLevel::Debug,
              ("nsDocShell %p UpdateActiveEntry (not replacing)", this));
      nsString title(mActiveEntry->GetTitle());
@@ -11075,7 +11068,7 @@ nsresult nsDocShell::UpdateURLAndHistory(Document* aDocument, nsIURI* aNewURI,
      // we'll just set mOSHE here.
      mOSHE = newSHEntry;
    }
-  } else if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+  } else if (mozilla::SessionHistoryInParent()) {
    MOZ_LOG(gSHLog, LogLevel::Debug,
            ("nsDocShell %p UpdateActiveEntry (replacing)", this));
    // Setting the resultPrincipalURI to nullptr is fine here: it will cause
@@ -11111,7 +11104,7 @@ nsresult nsDocShell::UpdateURLAndHistory(Document* aDocument, nsIURI* aNewURI,
    newSHEntry->SetLoadReplace(false);
  }

-  if (!StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+  if (!mozilla::SessionHistoryInParent()) {
    // Step 2.4 and 3: Modify new/original session history entry and clear its
    // POST data, if there is any.
    newSHEntry->SetStateData(aData);
@@ -11178,7 +11171,7 @@ nsresult nsDocShell::UpdateURLAndHistory(Document* aDocument, nsIURI* aNewURI,

 NS_IMETHODIMP
 nsDocShell::GetCurrentScrollRestorationIsManual(bool* aIsManual) {
-  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+  if (mozilla::SessionHistoryInParent()) {
    *aIsManual = mActiveEntry && mActiveEntry->GetScrollRestorationIsManual();
    return NS_OK;
  }
@@ -11286,8 +11279,7 @@ nsresult nsDocShell::AddToSessionHistory(
    nsISHEntry** aNewEntry) {
  MOZ_ASSERT(aURI, "uri is null");
  MOZ_ASSERT(!aChannel || !aTriggeringPrincipal, "Shouldn't have both set");
-  MOZ_DIAGNOSTIC_ASSERT(
-      !StaticPrefs::fission_sessionHistoryInParent_AtStartup());
+  MOZ_DIAGNOSTIC_ASSERT(!mozilla::SessionHistoryInParent());

 #if defined(DEBUG)
  if (MOZ_LOG_TEST(gDocShellLog, LogLevel::Debug)) {
@@ -11505,7 +11497,7 @@ void nsDocShell::UpdateActiveEntry(
    nsIContentSecurityPolicy* aCsp, const nsAString& aTitle,
    const Maybe<bool>& aScrollRestorationIsManual,
    nsIStructuredCloneContainer* aData, bool aURIWasModified) {
-  MOZ_ASSERT(StaticPrefs::fission_sessionHistoryInParent_AtStartup());
+  MOZ_ASSERT(mozilla::SessionHistoryInParent());
  MOZ_ASSERT(aURI, "uri is null");
  MOZ_ASSERT(mLoadType == LOAD_PUSHSTATE,
             "This code only deals with pushState");
@@ -11651,10 +11643,9 @@ NS_IMETHODIMP
 nsDocShell::PersistLayoutHistoryState() {
  nsresult rv = NS_OK;

-  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup() ? !!mActiveEntry
-                                                              : !!mOSHE) {
+  if (mozilla::SessionHistoryInParent() ? !!mActiveEntry : !!mOSHE) {
    bool scrollRestorationIsManual;
-    if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+    if (mozilla::SessionHistoryInParent()) {
      scrollRestorationIsManual = mActiveEntry->GetScrollRestorationIsManual();
    } else {
      scrollRestorationIsManual = mOSHE->GetScrollRestorationIsManual();
@@ -12102,7 +12093,7 @@ nsDocShell::GetIsExecutingOnLoadHandler(bool* aResult) {
 NS_IMETHODIMP
 nsDocShell::GetLayoutHistoryState(nsILayoutHistoryState** aLayoutHistoryState) {
  nsCOMPtr<nsILayoutHistoryState> state;
-  if (StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+  if (mozilla::SessionHistoryInParent()) {
    if (mActiveEntry) {
      state = mActiveEntry->GetLayoutHistoryState();
    }
@@ -12801,7 +12792,7 @@ nsDocShell::ResumeRedirectedLoad(uint64_t aIdentifier, int32_t aHistoryIndex) {
        // If we're performing a history load, locate the correct history entry,
        // and set the relevant bits on our loadState.
        if (aHistoryIndex >= 0 && self->GetSessionHistory() &&
-            !StaticPrefs::fission_sessionHistoryInParent_AtStartup()) {
+            !mozilla::SessionHistoryInParent()) {
          nsCOMPtr<nsISHistory> legacySHistory =
              self->GetSessionHistory()->LegacySHistory();

@@ -13194,7 +13185,7 @@ void nsDocShell::SetLoadingSessionHistoryInfo(
 }

 void nsDocShell::MoveLoadingToActiveEntry(bool aCommit) {
-  MOZ_ASSERT(StaticPrefs::fission_sessionHistoryInParent_AtStartup());
+  MOZ_ASSERT(mozilla::SessionHistoryInParent());

  MOZ_LOG(gSHLog, LogLevel::Debug,
          ("nsDocShell %p MoveLoadingToActiveEntry", this));