Add support for the audio-output-device switching IPC mechanism to the renderer lower layers (media…

media/base/audio_output_device_callback_util.cc

+// Copyright (c) 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 "media/base/audio_output_device_callback_util.h"
+
+#include "base/bind.h"
+#include "base/location.h"
+
+namespace media {
+
+SwitchOutputDeviceCallbackRunner::SwitchOutputDeviceCallbackRunner(
+    scoped_ptr<SwitchOutputDeviceCallback> callback,
+    const scoped_refptr<base::SingleThreadTaskRunner>& callback_task_runner)
+    : callback_(callback.Pass()),
+      callback_task_runner_(callback_task_runner) {}
+
+SwitchOutputDeviceCallbackRunner::~SwitchOutputDeviceCallbackRunner() {}
+
+static void RunCallback(scoped_ptr<SwitchOutputDeviceCallback> callback,
+                        SwitchOutputDeviceResult result) {
+  callback->Run(result);
+}
+
+void SwitchOutputDeviceCallbackRunner::Run(SwitchOutputDeviceResult result) {
+  if (callback_task_runner_) {
+    callback_task_runner_->PostTask(
+        FROM_HERE,
+        base::Bind(RunCallback, base::Passed(callback_.Pass()), result));
+    callback_task_runner_ = NULL;
+  }
+}
+
+}  // namespace media