Add decode() functionality to image elements.

content/renderer/gpu/render_widget_compositor.h

 // Copyright (c) 2013 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 CONTENT_RENDERER_GPU_RENDER_WIDGET_COMPOSITOR_H_
 #define CONTENT_RENDERER_GPU_RENDER_WIDGET_COMPOSITOR_H_
 
 #include <stdint.h>
 
 #include "base/callback.h"
@@ skipping 160 matching lines @@
   void setShowScrollBottleneckRects(bool show) override;
 
   void updateBrowserControlsState(blink::WebBrowserControlsState constraints,
                                   blink::WebBrowserControlsState current,
                                   bool animate) override;
   void setBrowserControlsHeight(float height, bool shrink) override;
   void setBrowserControlsShownRatio(float) override;
   // TODO(ianwen): Move this method to WebLayerTreeView and implement main
   // thread scrolling.
   virtual void setBottomControlsHeight(float height);
+  void requestDecode(sk_sp<SkImage> image,
+                     const base::Callback<void(bool)>& callback) override;
 
   // cc::LayerTreeHostClient implementation.
   void WillBeginMainFrame() override;
   void DidBeginMainFrame() override;
   void BeginMainFrame(const cc::BeginFrameArgs& args) override;
   void BeginMainFrameNotExpectedSoon() override;
   void UpdateLayerTreeHost() override;
   void ApplyViewportDeltas(const gfx::Vector2dF& inner_delta,
                            const gfx::Vector2dF& outer_delta,
                            const gfx::Vector2dF& elastic_overscroll_delta,
@@ skipping 48 matching lines @@
   blink::WebLayoutAndPaintAsyncCallback* layout_and_paint_async_callback_;
 
   cc::FrameSinkId frame_sink_id_;
 
   base::WeakPtrFactory<RenderWidgetCompositor> weak_factory_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_GPU_RENDER_WIDGET_COMPOSITOR_H_