Replaced cc::SurfaceId::nonce_ with base::UnguessableToken

content/browser/renderer_host/delegated_frame_host.cc

Index: content/browser/renderer_host/delegated_frame_host.cc
diff --git a/content/browser/renderer_host/delegated_frame_host.cc b/content/browser/renderer_host/delegated_frame_host.cc
index 2457eaef2925f40e7241def67cbd9667dd6f98ad..b150fe7c58c8f1972ffbc06ba3af4b43eff6ad96 100644
--- a/content/browser/renderer_host/delegated_frame_host.cc
+++ b/content/browser/renderer_host/delegated_frame_host.cc
@@ -216,7 +216,10 @@ cc::SurfaceId DelegatedFrameHost::SurfaceIdAtPoint(
     const gfx::Point& point,
     gfx::Point* transformed_point) {
   cc::SurfaceId surface_id(frame_sink_id_, local_frame_id_);
-  if (surface_id.is_null())
+  // TODO(staraz): Kludge: The is_null() check is causing tests to fail.
+  // The proper fix is to change it to is_valid which is going to be added in
+  // another CL
+  if (frame_sink_id_.is_null() || local_frame_id_.is_null())
     return surface_id;
   cc::SurfaceHittest hittest(delegate, GetSurfaceManager());
   gfx::Transform target_transform;