Split audio mixer into interface and implementation.

webrtc/api/audio/audio_mixer.h

 /*
  *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#ifndef WEBRTC_MODULES_AUDIO_MIXER_AUDIO_MIXER_H_
-#define WEBRTC_MODULES_AUDIO_MIXER_AUDIO_MIXER_H_
+#ifndef WEBRTC_API_AUDIO_AUDIO_MIXER_H_
+#define WEBRTC_API_AUDIO_AUDIO_MIXER_H_
 
 #include <memory>
 
 #include "webrtc/base/refcount.h"
 #include "webrtc/modules/include/module_common_types.h"
 
 namespace webrtc {
 
 class AudioMixer : public rtc::RefCountInterface {
  public:
@@ skipping 45 matching lines @@
   // Performs mixing by asking registered audio sources for audio. The
   // mixed result is placed in the provided AudioFrame. Will only be
   // called from a single thread. The rate and channels arguments
   // specify the rate and number of channels of the mix result.
   virtual void Mix(int sample_rate_hz,
                    size_t number_of_channels,
                    AudioFrame* audio_frame_for_mixing) = 0;
 };
 }  // namespace webrtc
 
-#endif  // WEBRTC_MODULES_AUDIO_MIXER_AUDIO_MIXER_H_
+#endif  // WEBRTC_API_AUDIO_AUDIO_MIXER_H_