Refactor browser process coordinate transformation methods

cc/surfaces/surface_hittest.h

Index: cc/surfaces/surface_hittest.h
diff --git a/cc/surfaces/surface_hittest.h b/cc/surfaces/surface_hittest.h
index 14f08455ec32e6cde9872bbbb6c614ebbee86cde..f934ad65db2f539bc2d146f7f1b098c3b3b88a3c 100644
--- a/cc/surfaces/surface_hittest.h
+++ b/cc/surfaces/surface_hittest.h
@@ -44,6 +44,14 @@ class CC_SURFACES_EXPORT SurfaceHittest {
                                    const SurfaceId& target_surface_id,
                                    gfx::Transform* transform);
 
+  // Attempts to transform a point from the coordinate space of one surface to
+  // that of another, where one is surface is embedded within the other.
+  // Returns true if the transform is successfully applied, and false if
+  // neither surface is contained with the other.
+  bool TransformPointToTargetSurface(const SurfaceId& original_surface_id,
+                                     const SurfaceId& target_surface_id,
+                                     gfx::Point* point);
+
  private:
   bool GetTargetSurfaceAtPointInternal(
       const SurfaceId& surface_id,