cc: Partial draw without partial swap support.

cc/output/output_surface.h

Index: cc/output/output_surface.h
diff --git a/cc/output/output_surface.h b/cc/output/output_surface.h
index d1715cbcdff4b45cdc50437272046a1d3e58ddfc..a1232dd1e6d60e64d6f6e0e35ecef78df97ce0c1 100644
--- a/cc/output/output_surface.h
+++ b/cc/output/output_surface.h
@@ -118,6 +118,10 @@ class CC_EXPORT OutputSurface {
   // after returning from this method in order to unblock the next frame.
   virtual void SwapBuffers(OutputSurfaceFrame frame) = 0;
 
+  // If this returns true, then partial draw of |damage| rect is supported
+  // by surface.
+  virtual bool CanPartialDraw(const gfx::Rect& damage) = 0;
+
  protected:
   struct OutputSurface::Capabilities capabilities_;
   scoped_refptr<ContextProvider> context_provider_;