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

ui/views/mus/window_manager_connection.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 UI_VIEWS_MUS_WINDOW_MANAGER_CONNECTION_H_
 #define UI_VIEWS_MUS_WINDOW_MANAGER_CONNECTION_H_
 
 #include <stdint.h>
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "components/mus/public/cpp/window_tree_delegate.h"
 #include "ui/views/mus/mus_export.h"
 #include "ui/views/mus/screen_mus_delegate.h"
 #include "ui/views/widget/widget.h"
 
 namespace mojo {
-class ApplicationImpl;
+class Shell;
 }
 
 namespace views {
 class NativeWidget;
 class ScreenMus;
 namespace internal {
 class NativeWidgetDelegate;
 }
 
 // Provides configuration to mus in views. This consists of the following:
 // . Provides a Screen implementation backed by mus.
 // . Creates and owns a WindowTreeConnection.
 // . Registers itself as the factory for creating NativeWidgets so that a
 //   NativeWidgetMus is created.
 // WindowManagerConnection is a singleton and should be created early on.
 //
 // TODO(sky): this name is now totally confusing. Come up with a better one.
 class VIEWS_MUS_EXPORT WindowManagerConnection
     : public NON_EXPORTED_BASE(mus::WindowTreeDelegate),
       public ScreenMusDelegate {
  public:
-  static void Create(mojo::ApplicationImpl* app);
+  static void Create(mojo::Shell* shell);
   static WindowManagerConnection* Get();
 
-  mojo::ApplicationImpl* app() { return app_; }
+  mojo::Shell* shell() { return shell_; }
 
   mus::Window* NewWindow(const std::map<std::string,
                          std::vector<uint8_t>>& properties);
 
  private:
-  explicit WindowManagerConnection(mojo::ApplicationImpl* app);
+  explicit WindowManagerConnection(mojo::Shell* shell);
   ~WindowManagerConnection() override;
 
   // mus::WindowTreeDelegate:
   void OnEmbed(mus::Window* root) override;
   void OnConnectionLost(mus::WindowTreeConnection* connection) override;
 
   // ScreenMusDelegate:
   void OnWindowManagerFrameValuesChanged() override;
 
   NativeWidget* CreateNativeWidget(const Widget::InitParams& init_params,
                                    internal::NativeWidgetDelegate* delegate);
 
-  mojo::ApplicationImpl* app_;
+  mojo::Shell* shell_;
   scoped_ptr<ScreenMus> screen_;
   scoped_ptr<mus::WindowTreeConnection> window_tree_connection_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowManagerConnection);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_MUS_WINDOW_MANAGER_CONNECTION_H_