ios: Cleanup class/struct forward declarations

ios/web/public/browser_state.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 IOS_WEB_PUBLIC_BROWSER_STATE_H_
 #define IOS_WEB_PUBLIC_BROWSER_STATE_H_
 
 #include "base/supports_user_data.h"
 
 namespace base {
 class FilePath;
 }
 
 namespace net {
 class URLRequestContextGetter;
 }
 
 namespace web {
 class ActiveStateManager;
-class BrowsingDataPartition;
 class CertificatePolicyCache;
 class URLDataManagerIOS;
 class URLDataManagerIOSBackend;
 class URLRequestChromeJob;
 
 // This class holds the context needed for a browsing session.
 // It lives on the UI thread. All these methods must only be called on the UI
 // thread.
 class BrowserState : public base::SupportsUserData {
  public:
@@ skipping 45 matching lines @@
 
   // The URLDataManagerIOSBackend instance associated with this BrowserState.
   // Created and destroyed on the IO thread, and should be accessed only from
   // the IO thread.
   URLDataManagerIOSBackend* url_data_manager_ios_backend_;
 };
 
 }  // namespace web
 
 #endif  // IOS_WEB_PUBLIC_BROWSER_STATE_H_