Refactoring ImageBuffer to decouple it from Canvas2DLayerBridge

Source/platform/graphics/ImageBufferSurface.h

Index: Source/platform/graphics/ImageBufferSurface.h
diff --git a/Source/platform/graphics/skia/GaneshUtils.h b/Source/platform/graphics/ImageBufferSurface.h
similarity index 58%
copy from Source/platform/graphics/skia/GaneshUtils.h
copy to Source/platform/graphics/ImageBufferSurface.h
index bc4c0cb6dae4f16484a510c29db5f98cc86045b3..a415cfa9e1877604fc84300c186dc94b196d4591 100644
--- a/Source/platform/graphics/skia/GaneshUtils.h
+++ b/Source/platform/graphics/ImageBufferSurface.h
@@ -28,18 +28,56 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef GaneshUtils_h
-#define GaneshUtils_h
+#ifndef ImageBufferSurface_h
+#define ImageBufferSurface_h
 
 #include "platform/PlatformExport.h"
 #include "platform/geometry/IntSize.h"
-#include "third_party/skia/include/core/SkBitmap.h"
-#include "third_party/skia/include/gpu/GrContext.h"
+#include "platform/graphics/GraphicsTypes3D.h"
+#include "wtf/FastAllocBase.h"
+#include "wtf/Noncopyable.h"
+
+class SkCanvas;
+class SkBitmap;
+
+namespace blink { class WebLayer; }
 
 namespace WebCore {
 
-bool PLATFORM_EXPORT ensureTextureBackedSkBitmap(GrContext*, SkBitmap&, const IntSize&, GrSurfaceOrigin, GrPixelConfig);
+enum OpacityMode {
+    NonOpaque,
+    Opaque,
+};
+
+class PLATFORM_EXPORT ImageBufferSurface {
+    WTF_MAKE_NONCOPYABLE(ImageBufferSurface); WTF_MAKE_FAST_ALLOCATED;
+public:
+    virtual ~ImageBufferSurface() { }
+
+    virtual SkCanvas* canvas() const = 0;
+    virtual const SkBitmap& bitmap() const;
+    virtual void willUse() { } // Called by ImageBuffer before reading or writing to the surface.
+    virtual bool isValid() const = 0;
+    virtual blink::WebLayer* layer() const { return 0; };
+    virtual bool isAccelerated() const { return false; }
+    virtual Platform3DObject getBackingTexture() const { return 0; }
+
+    OpacityMode opacityMode() const { return m_opacityMode; }
+    const IntSize& size() const { return m_size; }
+
+protected:
+    void clear();
+
+    ImageBufferSurface(const IntSize& size, OpacityMode opacityMode)
+        : m_opacityMode(opacityMode)
+        , m_size(size)
+    { }
+
+private:
+    OpacityMode m_opacityMode;
+    IntSize m_size;
+};
 
 } // namespace WebCore
 
-#endif // GaneshUtils_h
+#endif