content/child: Remove use of MessageLoopProxy and deprecated MessageLoop APIs

chrome/renderer/chrome_mock_render_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_RENDERER_CHROME_MOCK_RENDER_THREAD_H_
 #define CHROME_RENDERER_CHROME_MOCK_RENDER_THREAD_H_
 
 #include <string>
 
 #include "content/public/test/mock_render_thread.h"
 
 struct ExtensionMsg_ExternalConnectionInfo;
 
 // Extends content::MockRenderThread to know about extension messages.
 class ChromeMockRenderThread : public content::MockRenderThread {
  public:
   ChromeMockRenderThread();
   ~ChromeMockRenderThread() override;
 
   // content::RenderThread overrides.
-  scoped_refptr<base::MessageLoopProxy> GetIOMessageLoopProxy() override;
+  scoped_refptr<base::SingleThreadTaskRunner> GetIOMessageLoopProxy() override;
 
   //////////////////////////////////////////////////////////////////////////
   // The following functions are called by the test itself.
 
   // Set IO message loop proxy.
   void set_io_message_loop_proxy(
       const scoped_refptr<base::MessageLoopProxy>& proxy);
 
  private:
   // Overrides base class implementation to add custom handling for
   // print and extensions.
   bool OnMessageReceived(const IPC::Message& msg) override;
 
 #if defined(ENABLE_EXTENSIONS)
   // The callee expects to be returned a valid channel_id.
   void OnOpenChannelToExtension(int routing_id,
                                 const ExtensionMsg_ExternalConnectionInfo& info,
                                 const std::string& channel_name,
                                 bool include_tls_channel_id,
                                 int* port_id);
 #endif
 
   scoped_refptr<base::MessageLoopProxy> io_message_loop_proxy_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeMockRenderThread);
 };
 
 #endif  // CHROME_RENDERER_CHROME_MOCK_RENDER_THREAD_H_