ios: Cleanup class/struct forward declarations

ios/crnet/crnet_environment.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_CRNET_CRNET_ENVIRONMENT_H_
 #define IOS_CRNET_CRNET_ENVIRONMENT_H_
 
 #include <memory>
 
 #include "base/files/file_path.h"
 #include "base/macros.h"
 #include "base/message_loop/message_loop.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/threading/thread.h"
 #import "ios/crnet/CrNet.h"
 #include "net/url_request/url_request.h"
 #include "net/url_request/url_request_context.h"
 
 class JsonPrefStore;
 
 namespace net {
 class CookieStore;
-class HttpCache;
 class NetworkChangeNotifier;
 class NetLog;
 class ProxyConfigService;
 class SdchManager;
 class SdchOwner;
 class URLRequestContextGetter;
 class WriteToFileNetLogObserver;
 }
 
 class CrNetHttpProtocolHandlerDelegate;
@@ skipping 125 matching lines @@
       http_protocol_handler_delegate_;
   std::string user_agent_;
   bool user_agent_partial_;
   std::unique_ptr<net::NetLog> net_log_;
   std::unique_ptr<net::WriteToFileNetLogObserver> net_log_observer_;
 
   DISALLOW_COPY_AND_ASSIGN(CrNetEnvironment);
 };
 
 #endif  // IOS_CRNET_CRNET_ENVIRONMENT_H_