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"

[the sun, 2016/10/12 15:26:10]

This should be a forbidden inclusion?

[aleloi, 2016/10/12 15:36:02]

No, since GN currently doesn't know about module_common_types.h

[the sun, 2016/10/13 07:55:00]

kjellander@, is there a way to set GN up so only certain files can be included
from file in api/ ?

[aleloi, 2016/10/13 08:40:02]

I can attempt to answer that: you can declare some of the header files 'public'
by writing a 'public = [...]' section in the GN target. Then depending targets
are only allowed to include the public headers.

The problem is that GN only enforces that during 'gn check', and only targets
listed in .gn are checked before committing.

kjellander@, did I get something wrong?

 
 namespace webrtc {
 
 class AudioMixer : public rtc::RefCountInterface {
  public:
   // A callback class that all mixer participants must inherit from/implement.
   class Source {
    public:
     enum class AudioFrameInfo {
       kNormal,  // The samples in audio_frame are valid and should be used.
@@ skipping 40 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_