Move Image ownership out of CSSValue

Source/core/style/StylePendingImage.h

 /*
  * Copyright (C) 2010 Apple 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 61 matching lines @@
     DEFINE_INLINE_VIRTUAL_TRACE()
     {
         visitor->trace(m_value);
         StyleImage::trace(visitor);
     }
 
 private:
     explicit StylePendingImage(CSSValue* value)
         : m_value(value)
     {
+        printf("%p: StylePendingImage created\n", this);
         m_isPendingImage = true;
     }
 
     RawPtrWillBeMember<CSSValue> m_value; // Not retained; it owns us.
 };
 
 DEFINE_STYLE_IMAGE_TYPE_CASTS(StylePendingImage, isPendingImage());
 
 }
 #endif