Use the mojo::shell namespace consistently underly shell/.

shell/application_manager/application_loader.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 SHELL_APPLICATION_MANAGER_APPLICATION_LOADER_H_
 #define SHELL_APPLICATION_MANAGER_APPLICATION_LOADER_H_
 
 #include "base/callback.h"
 #include "mojo/public/cpp/system/core.h"
 #include "mojo/public/interfaces/application/shell.mojom.h"
 #include "mojo/services/network/public/interfaces/url_loader.mojom.h"
 #include "url/gurl.h"
 
 namespace mojo {
 
 class Application;
+
+namespace shell {
+
 class ApplicationManager;
 
 // Interface to implement special application loading behavior for a particular
 // URL or scheme.
 class ApplicationLoader {
  public:
   virtual ~ApplicationLoader() {}
 
   virtual void Load(const GURL& url,
                     InterfaceRequest<Application> application_request) = 0;
 
  protected:
   ApplicationLoader() {}
 };
 
+}  // namespace shell
 }  // namespace mojo
 
 #endif  // SHELL_APPLICATION_MANAGER_APPLICATION_LOADER_H_