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

components/web_view/public/cpp/web_view.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 "components/web_view/public/cpp/web_view.h"
 
 #include <stdint.h>
 #include <utility>
 
 #include "base/bind.h"
 #include "components/mus/public/cpp/window.h"
-#include "mojo/shell/public/cpp/application_impl.h"
+#include "mojo/shell/public/cpp/shell.h"
 
 namespace web_view {
 namespace {
 
 void OnEmbed(bool success, uint16_t connection_id) {
   CHECK(success);
 }
 
 }  // namespace
 
 WebView::WebView(mojom::WebViewClient* client) : binding_(client) {}
 WebView::~WebView() {}
 
-void WebView::Init(mojo::ApplicationImpl* app, mus::Window* window) {
+void WebView::Init(mojo::Shell* shell, mus::Window* window) {
   mojom::WebViewFactoryPtr factory;
-  app->ConnectToService("mojo:web_view", &factory);
+  shell->ConnectToService("mojo:web_view", &factory);
   factory->CreateWebView(binding_.CreateInterfacePtrAndBind(),
                          GetProxy(&web_view_));
 
   mus::mojom::WindowTreeClientPtr window_tree_client;
   web_view_->GetWindowTreeClient(GetProxy(&window_tree_client));
   window->Embed(std::move(window_tree_client),
                 mus::mojom::WindowTree::kAccessPolicyEmbedRoot,
                 base::Bind(&OnEmbed));
 }
 
 }  // namespace web_view