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

Source/core/html/canvas/WebGLContextObject.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
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  * 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 WebGLContextObject_h
 #define WebGLContextObject_h
 
 #include "core/html/canvas/WebGLObject.h"
-#include "core/platform/graphics/GraphicsContext3D.h"
 
 namespace WebCore {
 
 class GraphicsContext3D;
 class WebGLRenderingContext;
 
 // WebGLContextObject the base class for objects that are owned by a specific
 // WebGLRenderingContext.
 class WebGLContextObject : public WebGLObject {
 public:
@@ skipping 18 matching lines @@
 
     virtual GraphicsContext3D* getAGraphicsContext3D() const;
 
 private:
     WebGLRenderingContext* m_context;
 };
 
 } // namespace WebCore
 
 #endif // WebGLContextObject_h