EDK: Add a mojo::test::SimpleTestThread (and use it).

mojo/edk/test/simple_test_thread.cc

+// Copyright 2015 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/edk/test/simple_test_thread.h"
+
+#include "base/logging.h"
+
+namespace mojo {
+namespace test {
+
+SimpleTestThread::SimpleTestThread() : thread_(this, "SimpleTestThread") {}
+
+SimpleTestThread::~SimpleTestThread() {}
+
+void SimpleTestThread::Start() {
+  thread_.Start();
+}
+
+void SimpleTestThread::Join() {
+  thread_.Join();
+}
+
+}  // namespace test
+}  // namespace mojo