cleanup/ Remove unused forward declaration from app_window.h

extensions/browser/app_window/app_window.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_BROWSER_APP_WINDOW_APP_WINDOW_H_
 #define EXTENSIONS_BROWSER_APP_WINDOW_APP_WINDOW_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 15 matching lines @@
 
 namespace base {
 class DictionaryValue;
 }
 
 namespace content {
 class BrowserContext;
 class WebContents;
 }
 
-namespace ui {
-class BaseWindow;
-}
-
 namespace extensions {
 
 class AppDelegate;
 class AppWebContentsHelper;
 class Extension;
-class ExtensionRegistry;
 class NativeAppWindow;
 class PlatformAppBrowserTest;
-class WindowController;
 
 struct DraggableRegion;
 
 // Manages the web contents for app windows. The implementation for this
 // class should create and maintain the WebContents for the window, and handle
 // any message passing between the web contents and the extension system or
 // native window.
 class AppWindowContents {
  public:
   AppWindowContents() {}
@@ skipping 510 matching lines @@
   bool is_ime_window_;
 
   base::WeakPtrFactory<AppWindow> image_loader_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(AppWindow);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_APP_WINDOW_APP_WINDOW_H_