Mus+Ash: Use standard cc mechanism for surface lifetime.

services/ui/ws/server_window.cc

Index: services/ui/ws/server_window.cc
diff --git a/services/ui/ws/server_window.cc b/services/ui/ws/server_window.cc
index b15e52101cc96f01bd09556eaf41e21634538257..12a3c2679e3f7c0ad5255d708fdcddb95d078dfd 100644
--- a/services/ui/ws/server_window.cc
+++ b/services/ui/ws/server_window.cc
@@ -77,6 +77,10 @@ void ServerWindow::RemoveObserver(ServerWindowObserver* observer) {
   observers_.RemoveObserver(observer);
 }
 
+bool ServerWindow::HasObserver(ServerWindowObserver* observer) {
+  return observers_.HasObserver(observer);
+}
+
 void ServerWindow::CreateSurface(mojom::SurfaceType surface_type,
                                  mojo::InterfaceRequest<mojom::Surface> request,
                                  mojom::SurfaceClientPtr client) {
@@ -360,18 +364,6 @@ bool ServerWindow::IsDrawn() const {
   return root == window;
 }
 
-void ServerWindow::DestroySurfacesScheduledForDestruction() {
-  if (!surface_manager_)
-    return;
-  ServerWindowSurface* surface = surface_manager_->GetDefaultSurface();
-  if (surface)
-    surface->DestroySurfacesScheduledForDestruction();
-
-  surface = surface_manager_->GetUnderlaySurface();
-  if (surface)
-    surface->DestroySurfacesScheduledForDestruction();
-}
-
 ServerWindowSurfaceManager* ServerWindow::GetOrCreateSurfaceManager() {
   if (!surface_manager_.get())
     surface_manager_ = base::MakeUnique<ServerWindowSurfaceManager>(this);