URLFetcher uses a TaskRunner instead of a message loop.

net/url_request/url_fetcher_impl.cc

 // 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.
 
 #include "net/url_request/url_fetcher_impl.h"
 
 #include "base/bind.h"
 #include "base/message_loop_proxy.h"
 #include "net/url_request/url_fetcher_core.h"
 #include "net/url_request/url_fetcher_factory.h"
@@ skipping 86 matching lines @@
   return core_->GetMaxRetries();
 }
 
 
 base::TimeDelta URLFetcherImpl::GetBackoffDelay() const {
   return core_->GetBackoffDelay();
 }
 
 void URLFetcherImpl::SaveResponseToFileAtPath(
     const FilePath& file_path,
-    scoped_refptr<base::MessageLoopProxy> file_message_loop_proxy) {
-  core_->SaveResponseToFileAtPath(file_path, file_message_loop_proxy);
+    scoped_refptr<base::TaskRunner> file_task_runner) {
+  core_->SaveResponseToFileAtPath(file_path, file_task_runner);
 }
 
 void URLFetcherImpl::SaveResponseToTemporaryFile(
-    scoped_refptr<base::MessageLoopProxy> file_message_loop_proxy) {
-  core_->SaveResponseToTemporaryFile(file_message_loop_proxy);
+    scoped_refptr<base::TaskRunner> file_task_runner) {
+  core_->SaveResponseToTemporaryFile(file_task_runner);
 }
 
 HttpResponseHeaders* URLFetcherImpl::GetResponseHeaders() const {
   return core_->GetResponseHeaders();
 }
 
 HostPortPair URLFetcherImpl::GetSocketAddress() const {
   return core_->GetSocketAddress();
 }
 
@@ skipping 68 matching lines @@
 URLFetcherFactory* URLFetcherImpl::factory() {
   return g_factory;
 }
 
 // static
 void URLFetcherImpl::set_factory(URLFetcherFactory* factory) {
   g_factory = factory;
 }
 
 }  // namespace net