Cheaper thread-safe atomic initialization of static references.

Source/platform/heap/Handle.h

 /*
  * Copyright (C) 2014 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 151 matching lines @@
 
 private:
     static ThreadState* state() { return ThreadStateFor<Affinity>::state(); }
 };
 
 // RootsAccessor for Persistent that provides synchronized access to global
 // list of persistent handles. Can be used for persistent handles that are
 // passed between threads.
 class GlobalPersistents {
 public:
-    static PersistentNode* roots() { return ThreadState::globalRoots(); }
+    static PersistentNode* roots() { return &ThreadState::globalRoots(); }
 
     class Lock {
     public:
         Lock() : m_locker(ThreadState::globalRootsMutex()) { }
     private:
         MutexLocker m_locker;
     };
 };
 
 // Base class for persistent handles. RootsAccessor specifies which list to
@@ skipping 1001 matching lines @@
 template<typename T>
 struct ParamStorageTraits<RawPtr<T>> : public PointerParamStorageTraits<T*, blink::IsGarbageCollectedType<T>::value> {
 };
 
 template<typename T>
 PassRefPtr<T> adoptRef(blink::RefCountedGarbageCollected<T>*) = delete;
 
 } // namespace WTF
 
 #endif