Add //mojo/edk/platform/thread_utils.* containing "yield" and "sleep".

mojo/edk/platform/thread_utils.h

Index: mojo/edk/platform/thread_utils.h
diff --git a/mojo/edk/platform/thread_utils.h b/mojo/edk/platform/thread_utils.h
new file mode 100644
index 0000000000000000000000000000000000000000..0336b865dbae2fd3ef2a68eff0f6a69d579827bc
--- /dev/null
+++ b/mojo/edk/platform/thread_utils.h
@@ -0,0 +1,24 @@
+// Copyright 2016 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_PLATFORM_THREAD_UTILS_H_
+#define MOJO_EDK_PLATFORM_THREAD_UTILS_H_
+
+#include "mojo/public/c/system/types.h"
+
+namespace mojo {
+namespace platform {
+
+// Causes the calling thread to try to yield (allowing another thread to be
+// scheduled).
+void ThreadYield();
+
+// Causes the calling thread to sleep for at least the specified duration (which
+// must not be |MOJO_DEADLINE_INDEFINITE|).
+void ThreadSleep(MojoDeadline duration);
+
+}  // namespace platform
+}  // namespace mojo
+
+#endif  // MOJO_EDK_PLATFORM_THREAD_UTILS_H_