Improve DEFINE_STATIC_LOCAL()'s handling of Blink GCed objects.

third_party/WebKit/Source/core/html/HTMLFrameOwnerElement.cpp

 /*
  * Copyright (C) 2006, 2007, 2009 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 23 matching lines @@
 #include "core/loader/FrameLoader.h"
 #include "core/loader/FrameLoaderClient.h"
 #include "core/plugins/PluginView.h"
 #include "platform/weborigin/SecurityOrigin.h"
 
 namespace blink {
 
 typedef HeapHashMap<Member<Widget>, Member<FrameView>> WidgetToParentMap;
 static WidgetToParentMap& widgetNewParentMap()
 {
-    DEFINE_STATIC_LOCAL(Persistent<WidgetToParentMap>, map, (new WidgetToParentMap()));
-    return *map;
+    DEFINE_STATIC_LOCAL(WidgetToParentMap, map, (new WidgetToParentMap));
+    return map;
 }
 
 typedef HeapHashSet<Member<Widget>> WidgetSet;
 static WidgetSet& widgetsPendingTemporaryRemovalFromParent()
 {
     // Widgets in this set will not leak because it will be cleared in
     // HTMLFrameOwnerElement::UpdateSuspendScope::performDeferredWidgetTreeOperations.
-    DEFINE_STATIC_LOCAL(Persistent<WidgetSet>, set, (new WidgetSet()));
-    return *set;
+    DEFINE_STATIC_LOCAL(WidgetSet, set, (new WidgetSet));
+    return set;
 }
 
 HeapHashCountedSet<Member<Node>>& SubframeLoadingDisabler::disabledSubtreeRoots()
 {
-    DEFINE_STATIC_LOCAL(Persistent<HeapHashCountedSet<Member<Node>>>, nodes, (new HeapHashCountedSet<Member<Node>>()));
-    return *nodes;
+    DEFINE_STATIC_LOCAL(HeapHashCountedSet<Member<Node>>, nodes, (new HeapHashCountedSet<Member<Node>>));
+    return nodes;
 }
 
 static unsigned s_updateSuspendCount = 0;
 
 HTMLFrameOwnerElement::UpdateSuspendScope::UpdateSuspendScope()
 {
     ++s_updateSuspendCount;
 }
 
 void HTMLFrameOwnerElement::UpdateSuspendScope::performDeferredWidgetTreeOperations()
@@ skipping 236 matching lines @@
 DEFINE_TRACE(HTMLFrameOwnerElement)
 {
     visitor->trace(m_contentFrame);
     visitor->trace(m_widget);
     HTMLElement::trace(visitor);
     FrameOwner::trace(visitor);
 }
 
 
 } // namespace blink