Revert of Move content's shell connections to the IO thread

content/browser/renderer_host/render_process_host_impl.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_BROWSER_RENDERER_HOST_RENDER_PROCESS_HOST_IMPL_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_PROCESS_HOST_IMPL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 139 matching lines @@
   void ClearWebRtcLogMessageCallback() override;
   WebRtcStopRtpDumpCallback StartRtpDump(
       bool incoming,
       bool outgoing,
       const WebRtcRtpPacketCallback& packet_callback) override;
 #endif
   void ResumeDeferredNavigation(const GlobalRequestID& request_id) override;
   void NotifyTimezoneChange(const std::string& timezone) override;
   shell::InterfaceRegistry* GetInterfaceRegistry() override;
   shell::InterfaceProvider* GetRemoteInterfaces() override;
+  shell::Connection* GetChildConnection() override;
   std::unique_ptr<base::SharedPersistentMemoryAllocator> TakeMetricsAllocator()
       override;
   const base::TimeTicks& GetInitTimeForNavigationMetrics() const override;
 #if defined(ENABLE_BROWSER_CDMS)
   scoped_refptr<media::MediaKeys> GetCdm(int render_frame_id,
                                          int cdm_id) const override;
 #endif
   bool IsProcessBackgrounded() const override;
   void IncrementWorkerRefCount() override;
   void DecrementWorkerRefCount() override;
@@ skipping 340 matching lines @@
   mojo::ScopedMessagePipeHandle in_process_renderer_handle_;
 
   base::WeakPtrFactory<RenderProcessHostImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderProcessHostImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_PROCESS_HOST_IMPL_H_