Fix UpdateTilePriorities viewport in Android WebView.

cc/output/renderer.h

 // Copyright 2012 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 CC_OUTPUT_RENDERER_H_
 #define CC_OUTPUT_RENDERER_H_
 
 #include "base/basictypes.h"
 #include "cc/base/cc_export.h"
 #include "cc/quads/render_pass.h"
 #include "cc/trees/layer_tree_host.h"
 
 namespace cc {
 
 class CompositorFrameAck;
 class CompositorFrameMetadata;
 class ScopedResource;
 
 class CC_EXPORT RendererClient {
  public:
-  // Draw viewport in non-y-flipped window space. Note that while a draw is in
-  // progress, this is guaranteed to be contained within the output surface
-  // size.
+  // These return the draw viewport and clip in non-y-flipped window space.
+  // Note that while a draw is in progress, these are guaranteed to be
+  // contained within the output surface size.
   virtual gfx::Rect DeviceViewport() const = 0;
+  virtual gfx::Rect DeviceClip() const = 0;
 
   virtual float DeviceScaleFactor() const = 0;
   virtual const LayerTreeSettings& Settings() const = 0;
   virtual void SetFullRootLayerDamage() = 0;
   virtual bool HasImplThread() const = 0;
   virtual bool ShouldClearRootRenderPass() const = 0;
   virtual CompositorFrameMetadata MakeCompositorFrameMetadata() const = 0;
   virtual bool AllowPartialSwap() const = 0;
   virtual bool ExternalStencilTestEnabled() const = 0;
 
@@ skipping 51 matching lines @@
 
   RendererClient* client_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(Renderer);
 };
 
 }  // namespace cc
 
 #endif  // CC_OUTPUT_RENDERER_H_