Remove all remaining traces of MessageLoopProxy.

chrome/renderer/extensions/chrome_extensions_renderer_client.cc

 // Copyright 2014 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.
 
 #include "chrome/renderer/extensions/chrome_extensions_renderer_client.h"
 
 #include <memory>
 #include <utility>
 
 #include "base/command_line.h"
@@ skipping 135 matching lines @@
   permissions_policy_delegate_.reset(
       new extensions::RendererPermissionsPolicyDelegate(
           extension_dispatcher_.get()));
   resource_request_policy_.reset(
       new extensions::ResourceRequestPolicy(extension_dispatcher_.get()));
   guest_view_container_dispatcher_.reset(
       new extensions::ExtensionsGuestViewContainerDispatcher());
 
   thread->AddObserver(extension_dispatcher_.get());
   thread->AddObserver(guest_view_container_dispatcher_.get());
-  thread->AddFilter(new CastIPCDispatcher(thread->GetIOMessageLoopProxy()));
+  thread->AddFilter(new CastIPCDispatcher(thread->GetIOTaskRunner()));
 }
 
 void ChromeExtensionsRendererClient::RenderFrameCreated(
     content::RenderFrame* render_frame) {
   new extensions::ExtensionsRenderFrameObserver(render_frame);
   new extensions::ExtensionFrameHelper(render_frame,
                                        extension_dispatcher_.get());
   extension_dispatcher_->OnRenderFrameCreated(render_frame);
 }
 
@@ skipping 141 matching lines @@
 
 void ChromeExtensionsRendererClient::RunScriptsAtDocumentStart(
     content::RenderFrame* render_frame) {
   extension_dispatcher_->RunScriptsAtDocumentStart(render_frame);
 }
 
 void ChromeExtensionsRendererClient::RunScriptsAtDocumentEnd(
     content::RenderFrame* render_frame) {
   extension_dispatcher_->RunScriptsAtDocumentEnd(render_frame);
 }