Use ShellPtr type in ApplicationLoader instead of untyped handles

shell/android/background_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_ANDROID_BACKGROUND_APPLICATION_LOADER_H_
 #define SHELL_ANDROID_BACKGROUND_APPLICATION_LOADER_H_
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/threading/simple_thread.h"
 #include "shell/application_manager/application_loader.h"
 
 namespace mojo {
 
 class MOJO_APPLICATION_MANAGER_EXPORT BackgroundApplicationLoader
     : public ApplicationLoader,
       public base::DelegateSimpleThread::Delegate {
  public:
   BackgroundApplicationLoader(scoped_ptr<ApplicationLoader> real_loader,
                               const std::string& thread_name,
                               base::MessageLoop::Type message_loop_type);
   ~BackgroundApplicationLoader() override;
 
   // ApplicationLoader overrides:
   void Load(ApplicationManager* manager,
             const GURL& url,
-            ScopedMessagePipeHandle shell_handle,
+            ShellPtr shell,
             LoadCallback callback) override;
   void OnApplicationError(ApplicationManager* manager,
                           const GURL& url) override;
 
  private:
   // |base::DelegateSimpleThread::Delegate| method:
   void Run() override;
 
   // These functions are exected on the background thread. They call through
   // to |background_loader_| to do the actual loading.
   // TODO: having this code take a |manager| is fragile (as ApplicationManager
   // isn't thread safe).
   void LoadOnBackgroundThread(ApplicationManager* manager,
                               const GURL& url,
-                              ScopedMessagePipeHandle shell_handle);
+                              ShellPtr shell);
   void OnApplicationErrorOnBackgroundThread(ApplicationManager* manager,
                                             const GURL& url);
   bool quit_on_shutdown_;
   scoped_ptr<ApplicationLoader> loader_;
 
   const base::MessageLoop::Type message_loop_type_;
   const std::string thread_name_;
 
   // Created on |thread_| during construction of |this|. Protected against
   // uninitialized use by |message_loop_created_|, and protected against
   // use-after-free by holding a reference to the thread-safe object. Note
   // that holding a reference won't hold |thread_| from exiting.
   scoped_refptr<base::TaskRunner> task_runner_;
   base::WaitableEvent message_loop_created_;
 
   // Lives on |thread_|.
   base::Closure quit_closure_;
 
   scoped_ptr<base::DelegateSimpleThread> thread_;
 
   DISALLOW_COPY_AND_ASSIGN(BackgroundApplicationLoader);
 };
 
 }  // namespace mojo
 
 #endif  // SHELL_ANDROID_BACKGROUND_APPLICATION_LOADER_H_