ios: Cleanup class/struct forward declarations

ios/web/app/web_main_loop.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 IOS_WEB_APP_WEB_MAIN_LOOP_H_
 #define IOS_WEB_APP_WEB_MAIN_LOOP_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 
 namespace base {
-class CommandLine;
-class FilePath;
 class MessageLoop;
 class PowerMonitor;
 class SystemMonitor;
 }  // namespace base
 
 namespace net {
 class NetworkChangeNotifier;
 }  // namespace net
 
 namespace web {
@@ skipping 65 matching lines @@
 
   // Members initialized in |WebThreadsStarted()| --------------------------
   std::unique_ptr<CookieNotificationBridge> cookie_notification_bridge_;
 
   DISALLOW_COPY_AND_ASSIGN(WebMainLoop);
 };
 
 }  // namespace web
 
 #endif  // IOS_WEB_APP_WEB_MAIN_LOOP_H_