Cleanup: Remove unneeded forward declararations in net.

net/proxy/dhcp_proxy_script_adapter_fetcher_win.h

Index: net/proxy/dhcp_proxy_script_adapter_fetcher_win.h
===================================================================
--- net/proxy/dhcp_proxy_script_adapter_fetcher_win.h	(revision 109589)
+++ net/proxy/dhcp_proxy_script_adapter_fetcher_win.h	(working copy)
@@ -2,10 +2,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef NET_PROXY_DHCP_SCRIPT_ADAPTER_FETCHER_WIN_H_
-#define NET_PROXY_DHCP_SCRIPT_ADAPTER_FETCHER_WIN_H_
+#ifndef NET_PROXY_DHCP_PROXY_SCRIPT_ADAPTER_FETCHER_WIN_H_
+#define NET_PROXY_DHCP_PROXY_SCRIPT_ADAPTER_FETCHER_WIN_H_
 #pragma once
 
+#include <string>
+
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
@@ -16,10 +18,6 @@
 #include "net/base/net_export.h"
 #include "googleurl/src/gurl.h"
 
-namespace base {
-class MessageLoopProxy;
-}
-
 namespace net {
 
 class ProxyScriptFetcher;
@@ -180,4 +178,4 @@
 
 }  // namespace net
 
-#endif  // NET_PROXY_DHCP_SCRIPT_ADAPTER_FETCHER_WIN_H_
+#endif  // NET_PROXY_DHCP_PROXY_SCRIPT_ADAPTER_FETCHER_WIN_H_