Quit the message loop by default in ShellConnectionLost when ApplicationRunner is used

mash/quick_launch/quick_launch_application.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/quick_launch/quick_launch_application.h"
 
 #include "base/macros.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 88 matching lines @@
 
   views::Widget* window = views::Widget::CreateWindowWithBounds(
       new QuickLaunchUI(connector), gfx::Rect(10, 640, 0, 0));
   window->Show();
 }
 
 bool QuickLaunchApplication::AcceptConnection(mojo::Connection* connection) {
   return true;
 }
 
-void QuickLaunchApplication::ShellConnectionLost() {
-  base::MessageLoop::current()->QuitWhenIdle();
-}
-
 }  // namespace quick_launch
 }  // namespace mash