Fix bug in keeping capture in sync during destruction

ui/aura/test/mus/window_tree_client_private.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/aura/test/mus/window_tree_client_private.h"
 
 #include "ui/aura/mus/window_port_mus.h"
 #include "ui/aura/mus/window_tree_client.h"
 #include "ui/aura/window.h"
 #include "ui/display/display.h"
@@ skipping 48 matching lines @@
 void WindowTreeClientPrivate::CallOnCaptureChanged(Window* new_capture,
                                                    Window* old_capture) {
   tree_client_impl_->OnCaptureChanged(
       new_capture ? WindowPortMus::Get(new_capture)->server_id() : 0,
       old_capture ? WindowPortMus::Get(old_capture)->server_id() : 0);
 }
 
 void WindowTreeClientPrivate::SetTreeAndClientId(
     ui::mojom::WindowTree* window_tree,
     ClientSpecificId client_id) {
-  tree_client_impl_->tree_ = window_tree;
+  tree_client_impl_->WindowTreeConnectionEstablished(window_tree);
   tree_client_impl_->client_id_ = client_id;
 }
 
 bool WindowTreeClientPrivate::HasPointerWatcher() {
   return tree_client_impl_->has_pointer_watcher_;
 }
 
 }  // namespace aura