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

mojo/edk/base_edk/thread_utils.cc

+// 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.
+
+// This file implements the functions declared in
+// //mojo/edk/platform/thread_utils.h.
+
+#include "mojo/edk/platform/thread_utils.h"
+
+#include <stdint.h>
+
+#include <limits>
+
+#include "base/logging.h"
+#include "base/threading/platform_thread.h"
+#include "base/time/time.h"
+
+namespace mojo {
+namespace platform {
+
+void ThreadYield() {
+  base::PlatformThread::YieldCurrentThread();
+}
+
+void ThreadSleep(MojoDeadline duration) {
+  // Note: This also effectively checks that |duration| isn't
+  // |MOJO_DEADLINE_INDEFINITE|.
+  DCHECK_LE(duration,
+            static_cast<MojoDeadline>(std::numeric_limits<int64_t>::max()));
+
+  base::PlatformThread::Sleep(
+      base::TimeDelta::FromMicroseconds(static_cast<int64_t>(duration)));
+}
+
+}  // namespace platform
+}  // namespace mojo