Move DragImage from core/platform/ to platform/

Source/platform/DragImage.h

 /*
  * Copyright (C) 2007 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 19 matching lines @@
 #include "platform/graphics/ImageOrientation.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "wtf/Forward.h"
 
 namespace WebCore {
 
 class FontDescription;
 class Image;
 class KURL;
 
-class DragImage {
+class PLATFORM_EXPORT DragImage {
 public:
     static PassOwnPtr<DragImage> create(Image*, RespectImageOrientationEnum = DoNotRespectImageOrientation);
     static PassOwnPtr<DragImage> create(const KURL&, const String& label, const FontDescription& systemFont, float deviceScaleFactor);
     ~DragImage();
 
     const SkBitmap& bitmap() { return m_bitmap; }
     float resolutionScale() const { return m_resolutionScale; }
     IntSize size() const { return IntSize(m_bitmap.width(), m_bitmap.height()); }
 
     void fitToMaxSize(const IntSize& srcSize, const IntSize& maxSize);
     void scale(float scaleX, float scaleY);
     void dissolveToFraction(float fraction);
 
 private:
     DragImage(const SkBitmap&, float resolutionScale);
 
     SkBitmap m_bitmap;
     float m_resolutionScale;
 };
 
 }
 
 #endif // DragImage_h