Move the thread test helper to base/test

chrome/test/thread_test_helper.cc

-// Copyright (c) 2011 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/test/thread_test_helper.h"
-
-ThreadTestHelper::ThreadTestHelper(BrowserThread::ID thread_id)
-    : test_result_(false),
-      thread_id_(thread_id),
-      done_event_(false, false) {
-}
-
-bool ThreadTestHelper::Run() {
-  if (!BrowserThread::PostTask(thread_id_, FROM_HERE, NewRunnableMethod(
-          this, &ThreadTestHelper::RunInThread))) {
-    return false;
-  }
-  done_event_.Wait();
-  return test_result_;
-}
-
-void ThreadTestHelper::RunTest() { set_test_result(true); }
-
-ThreadTestHelper::~ThreadTestHelper() {}
-
-void ThreadTestHelper::RunInThread() {
-  RunTest();
-  done_event_.Signal();
-}