Remove unused includes from core/accessibility, core/css and core/dom

Source/core/css/CSSCrossfadeValue.h

 /*
  * Copyright (C) 2011 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 14 matching lines @@
 
 #ifndef CSSCrossfadeValue_h
 #define CSSCrossfadeValue_h
 
 #include "core/css/CSSImageGeneratorValue.h"
 #include "core/css/CSSPrimitiveValue.h"
 #include "core/loader/cache/CachedImage.h"
 #include "core/loader/cache/CachedImageClient.h"
 #include "core/loader/cache/CachedResourceHandle.h"
 #include "core/platform/graphics/Image.h"
-#include "core/platform/graphics/ImageObserver.h"
 
 namespace WebCore {
 
 class CachedImage;
 class CrossfadeSubimageObserverProxy;
 class RenderObject;
 class Document;
 
 class CSSCrossfadeValue : public CSSImageGeneratorValue {
     friend class CrossfadeSubimageObserverProxy;
@@ skipping 57 matching lines @@
     CachedResourceHandle<CachedImage> m_cachedToImage;
 
     RefPtr<Image> m_generatedImage;
 
     CrossfadeSubimageObserverProxy m_crossfadeSubimageObserver;
 };
 
 } // namespace WebCore
 
 #endif // CSSCrossfadeValue_h