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

mash/browser_driver/browser_driver_application_delegate.cc

 // Copyright 2015 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/browser_driver/browser_driver_application_delegate.h"
 
 #include <stdint.h>
 
 #include "base/bind.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 49 matching lines @@
     uint32_t id) {
   connector_ = connector;
   AddAccelerators();
 }
 
 bool BrowserDriverApplicationDelegate::AcceptConnection(
     mojo::Connection* connection) {
   return true;
 }
 
-void BrowserDriverApplicationDelegate::ShellConnectionLost() {
+bool BrowserDriverApplicationDelegate::ShellConnectionLost() {
   // Prevent the code in AddAccelerators() from keeping this app alive.
   binding_.set_connection_error_handler(base::Bind(&DoNothing));
-  base::MessageLoop::current()->QuitWhenIdle();
+  return true;
 }
 
 void BrowserDriverApplicationDelegate::OnAccelerator(
     uint32_t id, mus::mojom::EventPtr event) {
   switch (static_cast<Accelerator>(id)) {
     case Accelerator::NewWindow:
     case Accelerator::NewTab:
     case Accelerator::NewIncognitoWindow:
       connector_->Connect("exe:chrome");
       // TODO(beng): have Chrome export a service that allows it to be driven by
@@ skipping 23 matching lines @@
   for (const AcceleratorSpec& spec : g_spec) {
     registrar->AddAccelerator(
         static_cast<uint32_t>(spec.id),
         mus::CreateKeyMatcher(spec.keyboard_code, spec.event_flags),
         base::Bind(&AssertTrue));
   }
 }
 
 }  // namespace browser_driver
 }  // namespace main