Surface Synchronization: Distinguish between dependencies and references

cc/layers/surface_layer_impl.cc

Index: cc/layers/surface_layer_impl.cc
diff --git a/cc/layers/surface_layer_impl.cc b/cc/layers/surface_layer_impl.cc
index ed5b443ab0ad81cc75c7ca5918c1d9a155af3c33..4301c2ab4c07abb9fe626dd01c993d3e56987ebf 100644
--- a/cc/layers/surface_layer_impl.cc
+++ b/cc/layers/surface_layer_impl.cc
@@ -71,9 +71,9 @@ void SurfaceLayerImpl::AppendQuads(RenderPass* render_pass,
   // Emitting a fallback SurfaceDrawQuad is unnecessary if the primary and
   // fallback surface Ids match.
   if (primary && fallback_surface_info_.id() != primary_surface_info_.id()) {
-    primary->fallback_quad = CreateSurfaceDrawQuad(
-        render_pass, SurfaceDrawQuadType::FALLBACK, fallback_surface_info_,
-        &append_quads_data->embedded_surfaces);
+    primary->fallback_quad =
+        CreateSurfaceDrawQuad(render_pass, SurfaceDrawQuadType::FALLBACK,
+                              fallback_surface_info_, nullptr);

[vmpstr, 2017/04/11 18:35:17]

nit: comment like 

nullptr /* embedded_surfaces */);

[Fady Samuel, 2017/04/11 19:39:24]

Done.

   }
 }
 
@@ -121,7 +121,8 @@ SurfaceDrawQuad* SurfaceLayerImpl::CreateSurfaceDrawQuad(
       render_pass->CreateAndAppendDrawQuad<SurfaceDrawQuad>();
   surface_draw_quad->SetNew(shared_quad_state, quad_rect, visible_quad_rect,
                             surface_info.id(), surface_draw_quad_type, nullptr);
-  embedded_surfaces->push_back(surface_info.id());
+  if (embedded_surfaces)
+    embedded_surfaces->push_back(surface_info.id());
 
   return surface_draw_quad;
 }