Implement aura::WindowPortMus::CreateCompositorFrameSink()

ui/aura/mus/window_tree_client.cc

Index: ui/aura/mus/window_tree_client.cc
diff --git a/ui/aura/mus/window_tree_client.cc b/ui/aura/mus/window_tree_client.cc
index 6bb5e41fc0dc6f3f97a04fe27b4ef6f500e91f6e..7cfee1de7b69398d597f503956d7e64c36c34406 100644
--- a/ui/aura/mus/window_tree_client.cc
+++ b/ui/aura/mus/window_tree_client.cc
@@ -694,6 +694,12 @@ void WindowTreeClient::ScheduleInFlightBoundsChange(
       window->window_mus_type() == WindowMusType::DISPLAY_MANUALLY_CREATED) {
     local_surface_id = window->GetOrAllocateLocalSurfaceId(new_bounds.size());
     synchronizing_with_child_on_next_frame_ = true;
+  } else if (window->window_mus_type() == WindowMusType::LOCAL) {
+    auto id = window->GetOrAllocateLocalSurfaceId(new_bounds.size());
+    if (id.is_valid()) {
+      local_surface_id = id;
+      synchronizing_with_child_on_next_frame_ = true;
+    }
   }
   tree_->SetWindowBounds(change_id, window->server_id(), new_bounds,
                          local_surface_id);
@@ -1382,13 +1388,7 @@ void WindowTreeClient::OnWindowSurfaceChanged(
   WindowMus* window = GetWindowByServerId(window_id);
   if (!window)
     return;
-
-  // If the parent is informed of a child's surface then that surface ID is
-  // guaranteed to be available in the display compositor so we set it as the
-  // fallback. If surface synchronization is enabled, the primary SurfaceInfo
-  // is created by the embedder, and the LocalSurfaceId is allocated by the
-  // embedder.
-  window->SetFallbackSurfaceInfo(surface_info);
+  window->SetSurfaceInfoFromServer(surface_info);
 }
 
 void WindowTreeClient::OnDragDropStart(