Cheaper thread-safe atomic initialization of static references.

Source/platform/graphics/DeferredImageDecoderTest.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
@@ skipping 54 matching lines @@
     SkCanvas* canvas;
     SkPicture* picture;
 };
 
 } // namespace
 
 class DeferredImageDecoderTest : public ::testing::Test, public MockImageDecoderClient {
 public:
     virtual void SetUp() override
     {
-        ImageDecodingStore::instance()->setCacheLimitInBytes(1024 * 1024);
+        ImageDecodingStore::instance().setCacheLimitInBytes(1024 * 1024);
         DeferredImageDecoder::setEnabled(true);
         m_data = SharedBuffer::create(whitePNG, sizeof(whitePNG));
         m_frameCount = 1;
         OwnPtr<MockImageDecoder> decoder = MockImageDecoder::create(this);
         m_actualDecoder = decoder.get();
         m_actualDecoder->setSize(1, 1);
         m_lazyDecoder = DeferredImageDecoder::createForTesting(decoder.release());
         m_surface.reset(SkSurface::NewRasterN32Premul(100, 100));
         ASSERT_TRUE(m_surface.get());
         m_frameBufferRequestCount = 0;
         m_repetitionCount = cAnimationNone;
         m_status = ImageFrame::FrameComplete;
         m_frameDuration = 0;
         m_decodedSize = m_actualDecoder->size();
     }
 
     virtual void TearDown() override
     {
-        ImageDecodingStore::instance()->clear();
+        ImageDecodingStore::instance().clear();
     }
 
     virtual void decoderBeingDestroyed() override
     {
         m_actualDecoder = 0;
     }
 
     virtual void frameBufferRequested() override
     {
         ++m_frameBufferRequestCount;
@@ skipping 232 matching lines @@
     EXPECT_EQ(m_frameCount, m_lazyDecoder->frameCount());
     m_frameCount = 2;
     m_lazyDecoder->setData(*m_data, false);
     EXPECT_EQ(m_frameCount, m_lazyDecoder->frameCount());
     m_frameCount = 0;
     m_lazyDecoder->setData(*m_data, true);
     EXPECT_EQ(m_frameCount, m_lazyDecoder->frameCount());
 }
 
 } // namespace blink