Make ApplicationTestBase not use ApplicationImpl.

services/files/files_test_base.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 "services/files/files_test_base.h"
 
-#include "mojo/public/cpp/application/application_impl.h"
 #include "mojo/public/cpp/application/connect.h"
 #include "mojo/services/files/interfaces/files.mojom.h"
 #include "mojo/services/files/interfaces/types.mojom.h"
 
 namespace mojo {
 namespace files {
 
 FilesTestBase::FilesTestBase() {}
 
 FilesTestBase::~FilesTestBase() {}
 
 void FilesTestBase::SetUp() {
   test::ApplicationTestBase::SetUp();
-  ConnectToService(application_impl()->shell(), "mojo:files",
-                   GetSynchronousProxy(&files_));
+  ConnectToService(shell(), "mojo:files", GetSynchronousProxy(&files_));
 }
 
 void FilesTestBase::GetTemporaryRoot(
     SynchronousInterfacePtr<Directory>* directory) {
   Error error = Error::INTERNAL;
   ASSERT_TRUE(
       files_->OpenFileSystem(nullptr, GetSynchronousProxy(directory), &error));
   ASSERT_EQ(Error::OK, error);
 }
 
 void FilesTestBase::GetAppPersistentCacheRoot(
     SynchronousInterfacePtr<Directory>* directory) {
   Error error = Error::INTERNAL;
   ASSERT_TRUE(files_->OpenFileSystem("app_persistent_cache",
                                      GetSynchronousProxy(directory), &error));
   ASSERT_EQ(Error::OK, error);
 }
 
 }  // namespace files
 }  // namespace mojo