Get rid of KeepAlive. Quit shell when all urls run directly by Context are closed.

mojo/shell/dbus_application_loader_linux.h

 // Copyright 2014 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.
 
 #ifndef MOJO_SHELL_DBUS_APPLICATION_LOADER_LINUX_H_
 #define MOJO_SHELL_DBUS_APPLICATION_LOADER_LINUX_H_
 
 #include <map>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "mojo/application_manager/application_loader.h"
 #include "mojo/public/cpp/system/core.h"
-#include "mojo/shell/keep_alive.h"
 #include "url/gurl.h"
 
 namespace dbus {
 class Bus;
 }  // namespace dbus
 
 namespace mojo {
 namespace shell {
 
 class Context;
@@ skipping 55 matching lines @@
   typedef std::map<GURL, LoadContext*> LoadContextMap;
   LoadContextMap url_to_load_context_;
 
   DISALLOW_COPY_AND_ASSIGN(DBusApplicationLoader);
 };
 
 }  // namespace shell
 }  // namespace mojo
 
 #endif  // MOJO_SHELL_DBUS_APPLICATION_LOADER_LINUX_H_