Remove all remaining traces of MessageLoopProxy.

extensions/browser/api/serial/serial_apitest.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 <memory>
 #include <string>
 #include <utility>
 
 #include "base/macros.h"
 #include "chrome/browser/extensions/extension_apitest.h"
@@ skipping 118 matching lines @@
 }
 
 ExtensionFunction* FakeSerialConnectFunctionFactory() {
   return new FakeSerialConnectFunction();
 }
 
 void CreateTestSerialServiceOnFileThread(
     mojo::InterfaceRequest<device::serial::SerialService> request) {
   auto io_handler_factory = base::Bind(&FakeEchoSerialIoHandler::Create);
   auto* connection_factory = new device::SerialConnectionFactory(
-      io_handler_factory, content::BrowserThread::GetMessageLoopProxyForThread(
+      io_handler_factory, content::BrowserThread::GetTaskRunnerForThread(
                               content::BrowserThread::IO));
   std::unique_ptr<device::SerialDeviceEnumerator> device_enumerator(
       new FakeSerialDeviceEnumerator);
   new device::SerialServiceImpl(
       connection_factory, std::move(device_enumerator), std::move(request));
 }
 
 void CreateTestSerialService(
     mojo::InterfaceRequest<device::serial::SerialService> request) {
   content::BrowserThread::PostTask(
@@ skipping 46 matching lines @@
 IN_PROC_BROWSER_TEST_P(SerialApiTest, SerialRealHardware) {
   ResultCatcher catcher;
   catcher.RestrictToBrowserContext(browser()->profile());
 
   ASSERT_TRUE(RunExtensionTest("serial/real_hardware")) << message_;
 }
 
 INSTANTIATE_TEST_CASE_P(SerialApiTest, SerialApiTest, testing::Bool());
 
 }  // namespace extensions