Extract shell methods from ApplicationImpl into a base class, and pass this to Initialize() instead.

ui/views/mus/platform_test_helper_mus.cc

 // Copyright 2016 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 "ui/views/test/platform_test_helper.h"
 
 #include "base/path_service.h"
-#include "mojo/shell/public/cpp/application_impl.h"
 #include "mojo/shell/public/cpp/application_test_base.h"
+#include "mojo/shell/public/cpp/shell.h"
 #include "ui/aura/env.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/base/ui_base_paths.h"
 #include "ui/gl/test/gl_surface_test_support.h"
 #include "ui/views/mus/window_manager_connection.h"
 
 namespace views {
 namespace {
 
 class PlatformTestHelperMus : public PlatformTestHelper {
  public:
   PlatformTestHelperMus() {
     gfx::GLSurfaceTestSupport::InitializeOneOff();
 
     // TODO(sky): We really shouldn't need to configure ResourceBundle.
     ui::RegisterPathProvider();
     base::FilePath ui_test_pak_path;
     CHECK(PathService::Get(ui::UI_TEST_PAK, &ui_test_pak_path));
     ui::ResourceBundle::InitSharedInstanceWithPakPath(ui_test_pak_path);
     aura::Env::CreateInstance(true);
 
     mojo_test_helper_.reset(new mojo::test::TestHelper(nullptr));
     // ui/views/mus requires a WindowManager running, for now use the desktop
     // one.
-    mojo_test_helper_->application_impl()->ConnectToApplication(
-        "mojo:desktop_wm");
-    WindowManagerConnection::Create(mojo_test_helper_->application_impl());
+    mojo_test_helper_->shell()->ConnectToApplication("mojo:desktop_wm");
+    WindowManagerConnection::Create(mojo_test_helper_->shell());
   }
 
   ~PlatformTestHelperMus() override {
     mojo_test_helper_.reset(nullptr);
     aura::Env::DeleteInstance();
     ui::ResourceBundle::CleanupSharedInstance();
   }
 
  private:
   scoped_ptr<mojo::test::TestHelper> mojo_test_helper_;
 
   DISALLOW_COPY_AND_ASSIGN(PlatformTestHelperMus);
 };
 
 }  // namespace
 
 // static
 scoped_ptr<PlatformTestHelper> PlatformTestHelper::Create() {
   return make_scoped_ptr(new PlatformTestHelperMus);
 }
 
 }  // namespace views