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

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

Index: third_party/WebKit/Source/core/html/HTMLFrameOwnerElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLFrameOwnerElement.cpp b/third_party/WebKit/Source/core/html/HTMLFrameOwnerElement.cpp
index 03cc78f1b6474592a0171232787852f5d1a675b4..95fdf87e18ca4635a9270568dc3bafafaba4238b 100644
--- a/third_party/WebKit/Source/core/html/HTMLFrameOwnerElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLFrameOwnerElement.cpp
@@ -41,8 +41,8 @@ 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;
@@ -50,14 +50,14 @@ 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;