Cleanup: Remove more forward declarations in various chrome/browser directories.

chrome/browser/io_thread.h

 // Copyright (c) 2011 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_IO_THREAD_H_
 #define CHROME_BROWSER_IO_THREAD_H_
 #pragma once
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/task.h"
 #include "chrome/browser/net/ssl_config_service_manager.h"
 #include "chrome/browser/prefs/pref_member.h"
 #include "content/browser/browser_process_sub_thread.h"
 #include "net/base/network_change_notifier.h"
 
 class ChromeNetLog;
-class ChromeURLRequestContextGetter;
 class ExtensionEventRouterForwarder;
 class MediaInternals;
 class PrefProxyConfigTrackerImpl;
 class PrefService;
 class SystemURLRequestContextGetter;
 
-namespace base {
-class ListValue;
-}
-
 namespace net {
 class CertVerifier;
 class CookieStore;
 class DnsRRResolver;
 class FtpTransactionFactory;
 class HostResolver;
 class HttpAuthHandlerFactory;
 class HttpServerProperties;
 class HttpTransactionFactory;
 class NetworkDelegate;
@@ skipping 142 matching lines @@
       system_url_request_context_getter_;
 
   net::SdchManager* sdch_manager_;
 
   ScopedRunnableMethodFactory<IOThread> method_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(IOThread);
 };
 
 #endif  // CHROME_BROWSER_IO_THREAD_H_