Implement transform/clip support for Android WebView.

cc/output/output_surface_client.h

Index: cc/output/output_surface_client.h
diff --git a/cc/output/output_surface_client.h b/cc/output/output_surface_client.h
index cbb3b8c3a93d4e7c9d50beda7964a861606b618a..26edec803ad6be85d32b5a02606755d2aa1b9a44 100644
--- a/cc/output/output_surface_client.h
+++ b/cc/output/output_surface_client.h
@@ -9,6 +9,10 @@
 #include "cc/base/cc_export.h"
 #include "ui/gfx/rect.h"
 
+namespace gfx {
+class Transform;
+}
+
 namespace cc {
 
 class CompositorFrameAck;
@@ -23,6 +27,8 @@ class CC_EXPORT OutputSurfaceClient {
       const CompositorFrameAck& ack) = 0;
   virtual void OnSwapBuffersComplete() = 0;
   virtual void DidLoseOutputSurface() = 0;
+  virtual void SetExternalDrawConstraints(const gfx::Transform& transform,
+                                          gfx::Rect viewport) = 0;
 
  protected:
   virtual ~OutputSurfaceClient() {}