Use ShellPtr type in ApplicationLoader instead of untyped handles

shell/android/android_handler_loader.cc

 // 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.
 
 #include "shell/android/android_handler_loader.h"
 
 namespace mojo {
 namespace shell {
 
 AndroidHandlerLoader::AndroidHandlerLoader() {
 }
 
 AndroidHandlerLoader::~AndroidHandlerLoader() {
 }
 
 void AndroidHandlerLoader::Load(ApplicationManager* manager,
                                 const GURL& url,
-                                ScopedMessagePipeHandle shell_handle,
+                                ShellPtr shell,
                                 LoadCallback callback) {
-  DCHECK(shell_handle.is_valid());
-  application_.reset(
-      new ApplicationImpl(&android_handler_, shell_handle.Pass()));
+  DCHECK(shell);
+  application_.reset(new ApplicationImpl(&android_handler_, shell.Pass()));
 }
 
 void AndroidHandlerLoader::OnApplicationError(ApplicationManager* manager,
                                               const GURL& url) {
 }
 
 }  // namespace shell
 }  // namespace mojo