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

mash/example/window_type_launcher/window_type_launcher.h

 // 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.
 
 #ifndef MASH_EXAMPLE_WINDOW_TYPE_LAUNCHER_WINDOW_TYPE_LAUNCHER_H_
 #define MASH_EXAMPLE_WINDOW_TYPE_LAUNCHER_WINDOW_TYPE_LAUNCHER_H_
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "mojo/shell/public/cpp/application_delegate.h"
 
 namespace views {
 class AuraInit;
 }
 
 class WindowTypeLauncher : public mojo::ApplicationDelegate {
  public:
   WindowTypeLauncher();
   ~WindowTypeLauncher() override;
 
  private:
   // ApplicationDelegate:
-  void Initialize(mojo::ApplicationImpl* app) override;
+  void Initialize(mojo::Shell* shell, const std::string& url,
+                  uint32_t id) override;
   bool AcceptConnection(
       mojo::ApplicationConnection* connection) override;
 
   scoped_ptr<views::AuraInit> aura_init_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowTypeLauncher);
 };
 
 #endif  // MASH_EXAMPLE_WINDOW_TYPE_LAUNCHER_WINDOW_TYPE_LAUNCHER_H_