Bug 1362924 - Part 1: Stop synchronously running XBL constructors and flushing style in PresShell::Initialize. r=tnikkel

MozReview-Commit-ID: 8GUm6Mt5wiK

layout/base/PresShell.cpp

@@ -1708,6 +1708,24 @@ PresShell::EndObservingDocument()
 char* nsPresShell_ReflowStackPointerTop;
 #endif
 
+class XBLConstructorRunner : public Runnable
+{
+public:
+  explicit XBLConstructorRunner(nsIDocument* aDocument)
+    : mDocument(aDocument)
+  {
+  }
+
+  NS_IMETHOD Run() override
+  {
+    mDocument->BindingManager()->ProcessAttachedQueue();
+    return NS_OK;
+  }
+
+private:
+  nsCOMPtr<nsIDocument> mDocument;
+};
+
 nsresult
 PresShell::Initialize(nscoord aWidth, nscoord aHeight)
 {
@@ -1803,24 +1821,14 @@ PresShell::Initialize(nscoord aWidth, nscoord aHeight)
       mFrameConstructor->EndUpdate();
     }
 
-    // nsAutoScriptBlocker going out of scope may have killed us too
+    // nsAutoCauseReflowNotifier (which sets up a script blocker) going out of
+    // scope may have killed us too
     NS_ENSURE_STATE(!mHaveShutDown);
 
-    // Run the XBL binding constructors for any new frames we've constructed
-    mDocument->BindingManager()->ProcessAttachedQueue();
-
-    // Constructors may have killed us too
-    NS_ENSURE_STATE(!mHaveShutDown);
-
-    // Now flush out pending restyles before we actually reflow, in
-    // case XBL constructors changed styles somewhere.
-    {
-      nsAutoScriptBlocker scriptBlocker;
-      mPresContext->RestyleManager()->ProcessPendingRestyles();
-    }
-
-    // And that might have run _more_ XBL constructors
-    NS_ENSURE_STATE(!mHaveShutDown);
+    // Run the XBL binding constructors for any new frames we've constructed.
+    // (Do this in a script runner, since our caller might have a script
+    // blocker on the stack.)
+    nsContentUtils::AddScriptRunner(new XBLConstructorRunner(mDocument));
   }
 
   NS_ASSERTION(rootFrame, "How did that happen?");