Revert "content: Remove use of MessageLoopProxy and deprecated MessageLoop APIs"

content/public/browser/devtools_agent_host.h

 // Copyright (c) 2012 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 CONTENT_PUBLIC_BROWSER_DEVTOOLS_AGENT_HOST_H_
 #define CONTENT_PUBLIC_BROWSER_DEVTOOLS_AGENT_HOST_H_
 
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/message_loop/message_loop_proxy.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/devtools_agent_host_client.h"
 #include "url/gurl.h"
 
-namespace base {
-class SingleThreadTaskRunner;
-}
-
 namespace net {
 class ServerSocket;
 }
 
 namespace content {
 
 class BrowserContext;
 class DevToolsExternalAgentProxyDelegate;
 class WebContents;
 
@@ skipping 122 matching lines @@
   static void RemoveAgentStateCallback(const AgentStateCallback& callback);
 
  protected:
   friend class base::RefCounted<DevToolsAgentHost>;
   virtual ~DevToolsAgentHost() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_DEVTOOLS_AGENT_HOST_H_