Implement transform/clip support for Android WebView.

cc/trees/layer_tree_host_impl.h

Index: cc/trees/layer_tree_host_impl.h
diff --git a/cc/trees/layer_tree_host_impl.h b/cc/trees/layer_tree_host_impl.h
index 57221b2fdc084e3e9ce3fb4d9923bae653773d1a..e3615130c0589f7c4b244b37f29cab4cafd90b3d 100644
--- a/cc/trees/layer_tree_host_impl.h
+++ b/cc/trees/layer_tree_host_impl.h
@@ -195,6 +195,7 @@ class CC_EXPORT LayerTreeHostImpl
   virtual bool ShouldClearRootRenderPass() const OVERRIDE;
   virtual CompositorFrameMetadata MakeCompositorFrameMetadata() const OVERRIDE;
   virtual bool AllowPartialSwap() const OVERRIDE;
+  virtual gfx::Vector2d DeviceViewportOffset() const OVERRIDE;

[enne (OOO), 2013/05/29 20:34:12]

Unless I'm misunderstanding your requirements, it sounds like there are two
things you need from the output surface: a transform and a device viewport rect.
 However, I see viewport size, viewport offset, device clip, and device
transform.

Does it make sense to merge the viewport offset and size into just a rect? It
looks like that gets used in a number of places as a rect.

Also, is there a difference between viewport rect and device clip? Can these be
merged?

 
   // TileManagerClient implementation.
   virtual void ScheduleManageTiles() OVERRIDE;
@@ -203,6 +204,8 @@ class CC_EXPORT LayerTreeHostImpl
       OVERRIDE;
 
   // OutputSurfaceClient implementation.
+  virtual void SetDeviceTransformAndClip(const gfx::Transform& transform,
+                                         gfx::Rect clip) OVERRIDE;
   virtual void SetNeedsRedrawRect(gfx::Rect rect) OVERRIDE;
   virtual void OnVSyncParametersChanged(base::TimeTicks timebase,
                                         base::TimeDelta interval) OVERRIDE;
@@ -270,6 +273,9 @@ class CC_EXPORT LayerTreeHostImpl
   void SetDeviceScaleFactor(float device_scale_factor);
   float device_scale_factor() const { return device_scale_factor_; }
 
+  gfx::Rect DeviceClip() const;
+  gfx::Transform DeviceTransform() const;
+
   scoped_ptr<ScrollAndScaleSet> ProcessScrollDeltas();
 
   bool needs_animate_layers() const {
@@ -498,6 +504,8 @@ class CC_EXPORT LayerTreeHostImpl
   size_t last_sent_memory_use_bytes_;
 
   gfx::Rect viewport_damage_rect_;
+  gfx::Rect device_clip_;
+  gfx::Transform device_transform_;
 
   base::TimeTicks current_frame_timeticks_;
   base::Time current_frame_time_;