Don't cache any SkBitmaps in DeferredImageDecoder

Source/core/fetch/ImageResourceTest.cpp

 /*
  * Copyright (c) 2013, 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 201 matching lines @@
     cachedImage->finish();
     ASSERT_FALSE(cachedImage->errorOccurred());
     ASSERT_TRUE(cachedImage->hasImage());
     ASSERT_FALSE(cachedImage->image()->isNull());
     ASSERT_EQ(client.imageChangedCount(), 1);
     ASSERT_TRUE(client.notifyFinishedCalled());
 
     HashSet<ImageResource*> bitmapImages;
     ASSERT_TRUE(cachedImage->image()->isBitmapImage());
     bitmapImages.add(cachedImage.get());
-
-    // Updating bitmap resources produces image changed callbacks on their clients.
-    ImageResource::updateBitmapImages(bitmapImages);
-    ASSERT_EQ(client.imageChangedCount(), 2);
-    ImageResource::updateBitmapImages(bitmapImages, true);
-    ASSERT_EQ(client.imageChangedCount(), 3);
 }
 
 } // namespace