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..5d7570a496cedd28c87fe76a30e857a31652ef42 100644
--- a/content/browser/frame_host/cross_process_frame_connector.h
+++ b/content/browser/frame_host/cross_process_frame_connector.h
@@ -97,16 +97,19 @@ class CONTENT_EXPORT CrossProcessFrameConnector {
                                             const cc::SurfaceId& surface_id);
   // TransformPointToLocalCoordSpace() can only transform points between
   // 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.
-  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);
+  // other, and will return false if this is not the case. For points that can
+  // be in sibling surfaces, they must first be converted to the root
+  // surface's coordinate space.
+  bool TransformPointToLocalCoordSpace(const gfx::Point& point,
+                                       const cc::SurfaceId& original_surface,
+                                       const cc::SurfaceId& local_surface_id,
+                                       gfx::Point* transformed_point);
+  // Returns false if |target_view| and |view_| do not have the same root
+  // RenderWidgetHostView.
+  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,