Backed out changeset 9fa5c8e5fc13 (bug 1868023) for causing assertion failures in nsWindowMemoryReporter.cpp

docshell/base/nsDocShell.cpp

@@ -2708,6 +2708,25 @@ nsDocShell::GetInProcessSameTypeParent(nsIDocShellTreeItem** aParent) {
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsDocShell::GetSameTypeInProcessParentIgnoreBrowserBoundaries(
+    nsIDocShell** aParent) {
+  NS_ENSURE_ARG_POINTER(aParent);
+  *aParent = nullptr;
+
+  nsCOMPtr<nsIDocShellTreeItem> parent =
+      do_QueryInterface(GetAsSupports(mParent));
+  if (!parent) {
+    return NS_OK;
+  }
+
+  if (parent->ItemType() == mItemType) {
+    nsCOMPtr<nsIDocShell> parentDS = do_QueryInterface(parent);
+    parentDS.forget(aParent);
+  }
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsDocShell::GetInProcessRootTreeItem(nsIDocShellTreeItem** aRootTreeItem) {
   NS_ENSURE_ARG_POINTER(aRootTreeItem);

docshell/base/nsIDocShell.idl

@@ -539,6 +539,14 @@ interface nsIDocShell : nsIDocShellTreeItem
    */
   [infallible] readonly attribute boolean isTopLevelContentDocShell;
 
+  /**
+   * Like nsIDocShellTreeItem::GetSameTypeParent, except this ignores <iframe
+   * mozbrowser> boundaries. Which no longer exist.
+   *
+   * @deprecated: Use `BrowsingContext::GetParent()` in the future.
+   */
+  nsIDocShell getSameTypeInProcessParentIgnoreBrowserBoundaries();
+
   /**
    * True iff asynchronous panning and zooming is enabled for this
    * docshell.

dom/base/nsGlobalWindowOuter.cpp

@@ -3124,13 +3124,26 @@ nsPIDOMWindowOuter* nsGlobalWindowOuter::GetInProcessScriptableParentOrNull() {
   return (nsGlobalWindowOuter::Cast(parent) == this) ? nullptr : parent;
 }
 
+/**
+ * nsPIDOMWindow::GetParent (when called from C++) is just a wrapper around
+ * GetRealParent.
+ */
 already_AddRefed<nsPIDOMWindowOuter> nsGlobalWindowOuter::GetInProcessParent() {
-  if (auto* parentBC = GetBrowsingContext()->GetParent()) {
-    if (auto* parent = parentBC->GetDOMWindow()) {
-      return do_AddRef(parent);
-    }
+  if (!mDocShell) {
+    return nullptr;
   }
-  return do_AddRef(this);
+
+  nsCOMPtr<nsIDocShell> parent;
+  mDocShell->GetSameTypeInProcessParentIgnoreBrowserBoundaries(
+      getter_AddRefs(parent));
+
+  if (parent) {
+    nsCOMPtr<nsPIDOMWindowOuter> win = parent->GetWindow();
+    return win.forget();
+  }
+
+  nsCOMPtr<nsPIDOMWindowOuter> win(this);
+  return win.forget();
 }
 
 static nsresult GetTopImpl(nsGlobalWindowOuter* aWin, nsIURI* aURIBeingLoaded,

tools/lint/eslint/eslint-plugin-mozilla/tests/xpidl/docshell.xpt

@@ -2652,6 +2652,23 @@
           }
         ]
       },
+      {
+        "flags": [
+          "hasretval"
+        ],
+        "name": "getSameTypeInProcessParentIgnoreBrowserBoundaries",
+        "params": [
+          {
+            "flags": [
+              "out"
+            ],
+            "type": {
+              "name": "nsIDocShell",
+              "tag": "TD_INTERFACE_TYPE"
+            }
+          }
+        ]
+      },
       {
         "flags": [
           "getter",