Made MixerAudioSource a pure interface.

webrtc/modules/audio_mixer/audio_mixer_impl.h

Index: webrtc/modules/audio_mixer/audio_mixer_impl.h
diff --git a/webrtc/modules/audio_mixer/audio_mixer_impl.h b/webrtc/modules/audio_mixer/audio_mixer_impl.h
index ecfcbfa621d1d2213c719a23cc1331d90237c0b8..5e2478072320700cb9b896c6b19c67b543ec9fdd 100644
--- a/webrtc/modules/audio_mixer/audio_mixer_impl.h
+++ b/webrtc/modules/audio_mixer/audio_mixer_impl.h
@@ -15,11 +15,13 @@
 #include <memory>
 #include <vector>
 
+#include "webrtc/base/gtest_prod_util.h"
 #include "webrtc/base/thread_annotations.h"
 #include "webrtc/base/thread_checker.h"
 #include "webrtc/engine_configurations.h"
 #include "webrtc/modules/audio_mixer/audio_mixer.h"
 #include "webrtc/modules/audio_mixer/audio_mixer_defines.h"
+#include "webrtc/modules/audio_mixer/audio_source_with_mix_status.h"
 #include "webrtc/modules/audio_processing/include/audio_processing.h"
 #include "webrtc/modules/include/module_common_types.h"
 #include "webrtc/system_wrappers/include/critical_section_wrapper.h"
@@ -28,14 +30,14 @@
 namespace webrtc {
 
 typedef std::vector<AudioFrame*> AudioFrameList;
-typedef std::vector<MixerAudioSource*> MixerAudioSourceList;
+typedef std::vector<AudioSourceWithMixStatus> MixerAudioSourceList;

[aleloi, 2016/10/04 13:37:17]

Instead of storing lists of participant pointers, we store a list of
AudioSourceWithMixStatus. It's new class that is a wrapper around a participant
pointer and a flag that is |true| if the participant was mixer last round.

 
 class AudioMixerImpl : public AudioMixer {
  public:
   // AudioProcessing only accepts 10 ms frames.
   static const int kFrameDurationInMs = 10;
 
-  static std::unique_ptr<AudioMixer> Create(int id);
+  static std::unique_ptr<AudioMixerImpl> Create(int id);

[aleloi, 2016/10/04 13:37:16]

In order to allow the tests to access an AudioMixerImpl instance without having
to cast it. Note: we could make it public to avoid declaring it a friend of the
tests.

[ivoc, 2016/10/04 20:39:29]

Isn't this public already?

 
   ~AudioMixerImpl() override;
 
@@ -51,6 +53,8 @@ class AudioMixerImpl : public AudioMixer {
   bool AnonymousMixabilityStatus(
       const MixerAudioSource& audio_source) const override;
 
+  bool GetAudioSourceMixabilityStatus(MixerAudioSource* participant);
+

[aleloi, 2016/10/04 13:37:16]

Forgot to add a comment, see the next patch set.

  private:
   AudioMixerImpl(int id, std::unique_ptr<AudioProcessing> limiter);
 
@@ -61,11 +65,11 @@ class AudioMixerImpl : public AudioMixer {
   // Compute what audio sources to mix from audio_source_list_. Ramp
   // in and out. Update mixed status. Mixes up to
   // kMaximumAmountOfMixedAudioSources audio sources.
-  AudioFrameList GetNonAnonymousAudio() const EXCLUSIVE_LOCKS_REQUIRED(crit_);

[aleloi, 2016/10/04 13:37:16]

This function sets the mixed status of an AudioSourceWithStatus that is owned by
the mixer. Previously, it called (non-const) SetIsMixed on a participant
pointer, but now the mixer owns the status object.

+  AudioFrameList GetNonAnonymousAudio() EXCLUSIVE_LOCKS_REQUIRED(crit_);
 
   // Return the AudioFrames that should be mixed anonymously. Ramp in
   // and out. Update mixed status.
-  AudioFrameList GetAnonymousAudio() const EXCLUSIVE_LOCKS_REQUIRED(crit_);

[aleloi, 2016/10/04 13:37:16]

Same for this one.

+  AudioFrameList GetAnonymousAudio() EXCLUSIVE_LOCKS_REQUIRED(crit_);
 
   // This function returns true if it finds the MixerAudioSource in the
   // specified list of MixerAudioSources.
@@ -86,6 +90,8 @@ class AudioMixerImpl : public AudioMixer {
 
   int GetOutputAudioLevelFullRange() override;
 
+  AudioSourceWithMixStatus* GetSourceWithStatus(MixerAudioSource* audio_source);
+

[aleloi, 2016/10/04 13:37:16]

Comment added in next patch set.

   rtc::CriticalSection crit_;
 
   const int32_t id_;
@@ -117,6 +123,7 @@ class AudioMixerImpl : public AudioMixer {
   voe::AudioLevel audio_level_ ACCESS_ON(&thread_checker_);
 
   RTC_DISALLOW_COPY_AND_ASSIGN(AudioMixerImpl);
+  FRIEND_TEST_ALL_PREFIXES(AudioMixerTest, Create);

[aleloi, 2016/10/04 13:37:16]

Alternatively, we could make ::Create public.

 };
 }  // namespace webrtc