Remove unused includes from core/{editing,fileapi,history,html}

Source/core/html/canvas/CanvasRenderingContext.h

 /*
  * Copyright (C) 2009 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 10 matching lines @@
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
  */
 
 #ifndef CanvasRenderingContext_h
 #define CanvasRenderingContext_h
 
 #include "bindings/v8/ScriptWrappable.h"
 #include "core/html/HTMLCanvasElement.h"
-#include "core/platform/graphics/GraphicsLayer.h"
-#include <wtf/HashSet.h>
-#include <wtf/Noncopyable.h>
-#include <wtf/text/StringHash.h>
+#include "wtf/HashSet.h"
+#include "wtf/Noncopyable.h"
+#include "wtf/text/StringHash.h"
 
 namespace WebKit { class WebLayer; }
 
 namespace WebCore {
 
 class CanvasPattern;
 class HTMLCanvasElement;
 class HTMLImageElement;
 class HTMLVideoElement;
 class KURL;
@@ skipping 33 matching lines @@
     void checkOrigin(const KURL&);
 
 private:
     HTMLCanvasElement* m_canvas;
     HashSet<String> m_cleanURLs;
 };
 
 } // namespace WebCore
 
 #endif