Implement surface-based browser process hit testing for Mac and Aura

content/browser/compositor/delegated_frame_host.cc

Index: content/browser/compositor/delegated_frame_host.cc
diff --git a/content/browser/compositor/delegated_frame_host.cc b/content/browser/compositor/delegated_frame_host.cc
index 444adb8e929f372dd0c730f13bb6fe4a5b617a68..84e18d6855670ef4bd1eec8336a8d21516778a19 100644
--- a/content/browser/compositor/delegated_frame_host.cc
+++ b/content/browser/compositor/delegated_frame_host.cc
@@ -208,6 +208,8 @@ uint32_t DelegatedFrameHost::GetSurfaceIdNamespace() {
 cc::SurfaceId DelegatedFrameHost::SurfaceIdAtPoint(
     const gfx::Point& point,
     gfx::Point* transformed_point) {
+  if (surface_id_.is_null())
+    return surface_id_;
   cc::SurfaceHittest hittest(GetSurfaceManager());
   return hittest.Hittest(surface_id_, point, transformed_point);
 }