Add Audio support in Chromoting host when using WebRTC.

remoting/protocol/fake_audio_source.h

+// 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 REMOTING_PROTOCOL_FAKE_AUDIO_SOURCE_H_
+#define REMOTING_PROTOCOL_FAKE_AUDIO_SOURCE_H_
+
+#include "base/callback.h"
+#include "remoting/protocol/audio_source.h"
+
+namespace remoting {
+namespace protocol {
+
+class FakeAudioSource : public AudioSource {
+ public:
+  FakeAudioSource();
+  ~FakeAudioSource() override;
+
+  // AudioSource interface.
+  bool Start(const PacketCapturedCallback& callback) override;
+
+  const PacketCapturedCallback& callback() { return callback_; }
+
+ private:
+  PacketCapturedCallback callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(FakeAudioSource);
+};
+
+}  // namespace protocol
+}  // namespace remoting
+
+#endif  // REMOTING_PROTOCOL_FAKE_AUDIO_SOURCE_H_