chrome: Cleanup class/struct forward declarations

chrome/browser/extensions/api/tabs/windows_util.h

 // Copyright 2013 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 CHROME_BROWSER_EXTENSIONS_API_TABS_WINDOWS_UTIL_H__
 #define CHROME_BROWSER_EXTENSIONS_API_TABS_WINDOWS_UTIL_H__
 
 #include "chrome/browser/extensions/window_controller_list.h"
 
 class UIThreadExtensionFunction;
 
-namespace content {
-class BrowserContext;
-}
-
 namespace extensions {
-class Extension;
 class WindowController;
 }
 
 namespace windows_util {
 
 // Populates |controller| for given |window_id|. If the window is not found,
 // returns false and sets |error|.
 bool GetWindowFromWindowID(UIThreadExtensionFunction* function,
                            int window_id,
                            extensions::WindowController::TypeFilter filter,
                            extensions::WindowController** controller,
                            std::string* error);
 
 // Returns true if |function| (and the profile and extension that it was
 // invoked from) can operate on the window wrapped by |window_controller|.
 // If |all_window_types| is set this function will return true for any
 // kind of window (including app and devtools), otherwise it will
 // return true only for normal browser windows as well as windows
 // created by the extension.
 bool CanOperateOnWindow(const UIThreadExtensionFunction* function,
                         const extensions::WindowController* controller,
                         extensions::WindowController::TypeFilter filter);
 
 }  // namespace windows_util
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_TABS_WINDOWS_UTIL_H__