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

mojo/edk/test/simple_test_thread.h

Index: mojo/edk/test/simple_test_thread.h
diff --git a/mojo/edk/test/simple_test_thread.h b/mojo/edk/test/simple_test_thread.h
new file mode 100644
index 0000000000000000000000000000000000000000..36ec7cde81679b4ec58e0676f5de5585e599ff76
--- /dev/null
+++ b/mojo/edk/test/simple_test_thread.h
@@ -0,0 +1,40 @@
+// 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.
+
+#ifndef MOJO_EDK_TEST_SIMPLE_TEST_THREAD_
+#define MOJO_EDK_TEST_SIMPLE_TEST_THREAD_
+
+#include "base/threading/simple_thread.h"
+#include "mojo/public/cpp/system/macros.h"
+
+namespace mojo {
+namespace test {
+
+// Class to help simple threads (with no message loops) in tests.
+class SimpleTestThread : public base::DelegateSimpleThread::Delegate {
+ public:
+  SimpleTestThread();
+  ~SimpleTestThread() override;
+
+  // Starts the thread.
+  void Start();
+
+  // Joins the thread; this must be called if the thread was started.
+  void Join();
+
+  // Note: Subclasses must implement:

[vardhan, 2015/09/23 23:36:22]

Could this note be above the class?

[viettrungluu, 2015/09/23 23:37:13]

It could be, but it's sitting there as a placeholder for when I uncomment it.

+  //   virtual void Run() = 0;
+  // TODO(vtl): When we stop using |base::DelegateSimpleThread|, this will
+  // directly become part of our interface.
+
+ private:
+  base::DelegateSimpleThread thread_;
+
+  MOJO_DISALLOW_COPY_AND_ASSIGN(SimpleTestThread);
+};
+
+}  // namespace test
+}  // namespace mojo
+
+#endif  // MOJO_EDK_TEST_SIMPLE_TEST_THREAD_