extensions: Cleanup class/struct fwd declarations

extensions/shell/browser/desktop_controller.h

 // Copyright 2014 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 EXTENSIONS_SHELL_BROWSER_DESKTOP_CONTROLLER_H_
 #define EXTENSIONS_SHELL_BROWSER_DESKTOP_CONTROLLER_H_
 
 #include "ui/gfx/native_widget_types.h"
 
-namespace aura {
-class Window;
-class WindowTreeHost;
-}
-
 namespace content {
 class BrowserContext;
 }
 
 namespace gfx {
 class Size;
 }
 
 namespace extensions {
 class AppWindow;
 class Extension;
-class ShellAppWindow;
 
 // DesktopController is an interface to construct the window environment in
 // extensions shell. ShellDesktopControllerAura provides a default
 // implementation for app_shell, and other embedders can provide their own.
 // TODO(jamescook|oshima): Clean up this interface now that there is only one
 // way to create an app window.
 class DesktopController {
  public:
   DesktopController();
   virtual ~DesktopController();
@@ skipping 19 matching lines @@
   // Removes the window from the desktop.
   virtual void RemoveAppWindow(AppWindow* window) = 0;
 
   // Closes and destroys the app windows.
   virtual void CloseAppWindows() = 0;
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_SHELL_BROWSER_DESKTOP_CONTROLLER_H_