Mojo: Replace TestWithIOThreadBase with just a helper TestIOThread class.

mojo/system/test_utils.cc

 // Copyright 2013 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 "mojo/system/test_utils.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/synchronization/waitable_event.h"
 
@@ skipping 13 matching lines @@
 
 void PostTaskAndWait(scoped_refptr<base::TaskRunner> task_runner,
                      const tracked_objects::Location& from_here,
                      const base::Closure& task) {
   base::WaitableEvent event(false, false);
   task_runner->PostTask(from_here,
                         base::Bind(&PostTaskAndWaitHelper, &event, task));
   event.Wait();
 }
 
-// TestWithIOThreadBase --------------------------------------------------------
+// TestIOThread ----------------------------------------------------------------
 
-TestWithIOThreadBase::TestWithIOThreadBase() : io_thread_("io_thread") {
-}
-
-TestWithIOThreadBase::~TestWithIOThreadBase() {
-}
-
-void TestWithIOThreadBase::SetUp() {
+TestIOThread::TestIOThread() : io_thread_("test_io_thread") {
   io_thread_.StartWithOptions(
       base::Thread::Options(base::MessageLoop::TYPE_IO, 0));
 }
 
-void TestWithIOThreadBase::TearDown() {
+TestIOThread::~TestIOThread() {
   io_thread_.Stop();
 }
 
 }  // namespace test
 }  // namespace system
 }  // namespace mojo