Cheaper thread-safe atomic initialization of static references.

Source/platform/graphics/ImageDecodingStore.cpp

 /*
  * Copyright (C) 2012 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 35 matching lines @@
 ImageDecodingStore::~ImageDecodingStore()
 {
 #if ENABLE(ASSERT)
     setCacheLimitInBytes(0);
     ASSERT(!m_decoderCacheMap.size());
     ASSERT(!m_orderedCacheList.size());
     ASSERT(!m_decoderCacheKeyMap.size());
 #endif
 }
 
-ImageDecodingStore* ImageDecodingStore::instance()
+ImageDecodingStore& ImageDecodingStore::instance()
 {
-    AtomicallyInitializedStatic(ImageDecodingStore*, store = ImageDecodingStore::create().leakPtr());
+    AtomicallyInitializedStaticReference(ImageDecodingStore, store, ImageDecodingStore::create().leakPtr());
     return store;
 }
 
 bool ImageDecodingStore::lockDecoder(const ImageFrameGenerator* generator, const SkISize& scaledSize, ImageDecoder** decoder)
 {
     ASSERT(decoder);
 
     MutexLocker lock(m_mutex);
     DecoderCacheMap::iterator iter = m_decoderCacheMap.find(DecoderCacheEntry::makeCacheKey(generator, scaledSize));
     if (iter == m_decoderCacheMap.end())
@@ skipping 213 matching lines @@
     }
 }
 
 void ImageDecodingStore::removeFromCacheListInternal(const Vector<OwnPtr<CacheEntry>>& deletionList)
 {
     for (size_t i = 0; i < deletionList.size(); ++i)
         m_orderedCacheList.remove(deletionList[i].get());
 }
 
 } // namespace blink