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

components/html_viewer/content_handler_impl.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/html_viewer/content_handler_impl.h"
 
 #include <utility>
 
 #include "components/html_viewer/html_document_application_delegate.h"
 
 namespace html_viewer {
 
 ContentHandlerImpl::ContentHandlerImpl(
     GlobalState* global_state,
-    mojo::ApplicationImpl* app,
+    mojo::Shell* shell,
     mojo::InterfaceRequest<mojo::shell::mojom::ContentHandler> request)
     : global_state_(global_state),
-      app_(app),
+      shell_(shell),
       binding_(this, std::move(request)),
-      app_refcount_(app_->app_lifetime_helper()->CreateAppRefCount()) {}
+      app_refcount_(shell_->CreateAppRefCount()) {}
 
 ContentHandlerImpl::~ContentHandlerImpl() {
 }
 
 void ContentHandlerImpl::StartApplication(
     mojo::ApplicationRequest request,
     mojo::URLResponsePtr response,
     const mojo::Callback<void()>& destruct_callback) {
   // HTMLDocumentApplicationDelegate deletes itself.
   new HTMLDocumentApplicationDelegate(
       std::move(request), std::move(response), global_state_,
-      app_->app_lifetime_helper()->CreateAppRefCount(), destruct_callback);
+      shell_->CreateAppRefCount(), destruct_callback);
 }
 
 }  // namespace html_viewer