Streamline the presentation of ImageBitmapRenderingContext

third_party/WebKit/Source/modules/imagebitmap/ImageBitmapRenderingContext.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ImageBitmapRenderingContext_h
 #define ImageBitmapRenderingContext_h
 
 #include "core/html/canvas/CanvasRenderingContext.h"
 #include "core/html/canvas/CanvasRenderingContextFactory.h"
 #include "modules/ModulesExport.h"
 #include "wtf/RefPtr.h"
 
 namespace blink {
 
 class ImageBitmap;
+class ImageLayerBridge;
 
 class MODULES_EXPORT ImageBitmapRenderingContext final
     : public CanvasRenderingContext {
   DEFINE_WRAPPERTYPEINFO();
 
  public:
   class Factory : public CanvasRenderingContextFactory {
     WTF_MAKE_NONCOPYABLE(Factory);
 
    public:
     Factory() {}
     ~Factory() override {}
 
     CanvasRenderingContext* create(HTMLCanvasElement*,
                                    const CanvasContextCreationAttributes&,
                                    Document&) override;
     CanvasRenderingContext::ContextType getContextType() const override {
       return CanvasRenderingContext::ContextImageBitmap;
     }
   };
 
+  DECLARE_TRACE();
+
   // Script API
   void transferFromImageBitmap(ImageBitmap*, ExceptionState&);
 
   // CanvasRenderingContext implementation
   ContextType getContextType() const override {
     return CanvasRenderingContext::ContextImageBitmap;
   }
   void setIsHidden(bool) override {}
   bool isContextLost() const override { return false; }
-  bool paint(GraphicsContext&, const IntRect&) override;
   void setCanvasGetContextResult(RenderingContext&) final;
-  PassRefPtr<Image> getImage(AccelerationHint, SnapshotReason) const final {
-    return m_image.get();
-  }
+  PassRefPtr<Image> getImage(AccelerationHint, SnapshotReason) const final;
+  bool isComposited() const final { return true; }
+  bool isAccelerated() const final;
 
-  // TODO(junov): Implement GPU accelerated rendering using a layer bridge
-  WebLayer* platformLayer() const override { return nullptr; }
+  WebLayer* platformLayer() const final;
   // TODO(junov): handle lost contexts when content is GPU-backed
   void loseContext(LostContextMode) override {}
 
   void stop() override;
 
-  bool isPaintable() const final { return m_image.get(); }
+  bool isPaintable() const final;
 
   virtual ~ImageBitmapRenderingContext();
 
  private:
   ImageBitmapRenderingContext(HTMLCanvasElement*,
                               const CanvasContextCreationAttributes&,
                               Document&);
 
-  RefPtr<Image> m_image;
+  Member<ImageLayerBridge> m_imageLayerBridge;
 };
 
 DEFINE_TYPE_CASTS(ImageBitmapRenderingContext,
                   CanvasRenderingContext,
                   context,
                   context->getContextType() ==
                       CanvasRenderingContext::ContextImageBitmap,
                   context.getContextType() ==
                       CanvasRenderingContext::ContextImageBitmap);
 
 }  // blink
 
 #endif