Bug 1597442 - Remove the usage of nsIDocShellTreeItem from nsJSContext::MaybeRunNextCollectorSlice(). r=smaug

Differential Revision: https://phabricator.services.mozilla.com/D63609

--HG--
extra : moz-landing-system : lando

dom/base/nsJSEnvironment.cpp

@@ -52,6 +52,7 @@
 #include "mozilla/PresShell.h"
 #include "mozilla/StaticPrefs_javascript.h"
 #include "mozilla/StaticPtr.h"
+#include "mozilla/dom/BrowsingContext.h"
 #include "mozilla/dom/DOMException.h"
 #include "mozilla/dom/DOMExceptionBinding.h"
 #include "mozilla/dom/Element.h"
@@ -2012,14 +2013,23 @@ void nsJSContext::MaybeRunNextCollectorSlice(nsIDocShell* aDocShell,
     return;
   }
 
-  nsCOMPtr<nsIDocShellTreeItem> root;
-  aDocShell->GetInProcessSameTypeRootTreeItem(getter_AddRefs(root));
-  if (root == aDocShell) {
+  BrowsingContext* bc = aDocShell->GetBrowsingContext();
+  if (!bc) {
+    return;
+  }
+
+  BrowsingContext* root = bc->Top();
+  if (bc == root) {
     // We don't want to run collectors when loading the top level page.
     return;
   }
 
-  Document* rootDocument = root->GetDocument();
+  nsIDocShell* rootDocShell = root->GetDocShell();
+  if (!rootDocShell) {
+    return;
+  }
+
+  Document* rootDocument = rootDocShell->GetDocument();
   if (!rootDocument ||
       rootDocument->GetReadyStateEnum() != Document::READYSTATE_COMPLETE ||
       rootDocument->IsInBackgroundWindow()) {