mash/wm: Fix detecting container windows.

mash/wm/disconnected_app_handler.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 "mash/wm/disconnected_app_handler.h"
+
+namespace mash {
+namespace wm {
+
+DisconnectedAppHandler::DisconnectedAppHandler() {}
+
+DisconnectedAppHandler::~DisconnectedAppHandler() {}
+
+void DisconnectedAppHandler::OnWindowEmbeddedAppDisconnected(
+    mus::Window* window) {
+  window->Destroy();
+}
+
+}  // namespace wm
+}  // namespace mash