Account for failure of coordinate space transformations in browser

content/browser/frame_host/cross_process_frame_connector.h

Index: content/browser/frame_host/cross_process_frame_connector.h
diff --git a/content/browser/frame_host/cross_process_frame_connector.h b/content/browser/frame_host/cross_process_frame_connector.h
index 1eb930492dfa3a17ba4e65177022451db12d759e..6bee819df5027dc7bc4fcd6220dea4dc1ff7c22f 100644
--- a/content/browser/frame_host/cross_process_frame_connector.h
+++ b/content/browser/frame_host/cross_process_frame_connector.h
@@ -99,14 +99,14 @@ class CONTENT_EXPORT CrossProcessFrameConnector {
   // surfaces where one is embedded (not necessarily directly) within the
   // other. For points that can be in sibling surfaces, they must first be
   // converted to the root surface's coordinate space.

[ncarter (slow), 2016/10/13 20:34:42]

Document the return value (and maybe give an example of why failure might
occur?).

[kenrb, 2016/10/14 13:02:43]

Done.

-  gfx::Point TransformPointToLocalCoordSpace(
-      const gfx::Point& point,
-      const cc::SurfaceId& original_surface,
-      const cc::SurfaceId& local_surface_id);
-  gfx::Point TransformPointToCoordSpaceForView(
-      const gfx::Point& point,
-      RenderWidgetHostViewBase* target_view,
-      const cc::SurfaceId& local_surface_id);
+  bool TransformPointToLocalCoordSpace(const gfx::Point& point,
+                                       const cc::SurfaceId& original_surface,
+                                       const cc::SurfaceId& local_surface_id,
+                                       gfx::Point* transformed_point);
+  bool TransformPointToCoordSpaceForView(const gfx::Point& point,
+                                         RenderWidgetHostViewBase* target_view,
+                                         const cc::SurfaceId& local_surface_id,
+                                         gfx::Point* transformed_point);
 
   // Pass acked touch events to the root view for gesture processing.
   void ForwardProcessAckedTouchEvent(const TouchEventWithLatencyInfo& touch,