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

third_party/WebKit/Source/core/dom/Node.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 110 matching lines @@
 {
     ASSERT(isMainThread());
     partitionFree(ptr);
 }
 #endif
 
 #if DUMP_NODE_STATISTICS
 using WeakNodeSet = HeapHashSet<WeakMember<Node>>;
 static WeakNodeSet& liveNodeSet()
 {
-    DEFINE_STATIC_LOCAL(Persistent<WeakNodeSet>, set, (new WeakNodeSet()));
-    return *set;
+    DEFINE_STATIC_LOCAL(WeakNodeSet, set, (new WeakNodeSet));
+    return set;
 }
 #endif
 
 void Node::dumpStatistics()
 {
 #if DUMP_NODE_STATISTICS
     size_t nodesWithRareData = 0;
 
     size_t elementNodes = 0;
     size_t attrNodes = 0;
@@ skipping 1736 matching lines @@
     for (Node& node : NodeTraversal::startsAt(this)) {
         node.removeAllEventListeners();
         for (ShadowRoot* root = node.youngestShadowRoot(); root; root = root->olderShadowRoot())
             root->removeAllEventListenersRecursively();
     }
 }
 
 using EventTargetDataMap = HeapHashMap<WeakMember<Node>, Member<EventTargetData>>;
 static EventTargetDataMap& eventTargetDataMap()
 {
-    DEFINE_STATIC_LOCAL(Persistent<EventTargetDataMap>, map, (new EventTargetDataMap()));
-    return *map;
+    DEFINE_STATIC_LOCAL(EventTargetDataMap, map, (new EventTargetDataMap));
+    return map;
 }
 
 EventTargetData* Node::eventTargetData()
 {
     return hasEventTargetData() ? eventTargetDataMap().get(this) : nullptr;
 }
 
 EventTargetData& Node::ensureEventTargetData()
 {
     if (hasEventTargetData())
@@ skipping 548 matching lines @@
 
 void showNodePath(const blink::Node* node)
 {
     if (node)
         node->showNodePathForThis();
     else
         fprintf(stderr, "Cannot showNodePath for (nil)\n");
 }
 
 #endif