Makes WindowTree::DeleteWindow() unembed for roots

services/ui/ws/window_server.cc

Index: services/ui/ws/window_server.cc
diff --git a/services/ui/ws/window_server.cc b/services/ui/ws/window_server.cc
index f4d9a4ec082a6ee855a047df80d7a017b7b147d6..1f6d33dfde4b975f0190754a835a9268c33ff704 100644
--- a/services/ui/ws/window_server.cc
+++ b/services/ui/ws/window_server.cc
@@ -422,7 +422,7 @@ void WindowServer::ProcessWindowReorder(const ServerWindow* window,
   }
 }
 
-void WindowServer::ProcessWindowDeleted(const ServerWindow* window) {
+void WindowServer::ProcessWindowDeleted(ServerWindow* window) {
   for (auto& pair : tree_map_)
     pair.second->ProcessWindowDeleted(window, IsOperationSource(pair.first));
 }