Stylizing AudioConferenceMixer.

webrtc/modules/audio_conference_mixer/interface/audio_conference_mixer.h

Index: webrtc/modules/audio_conference_mixer/interface/audio_conference_mixer.h
diff --git a/webrtc/modules/audio_conference_mixer/interface/audio_conference_mixer.h b/webrtc/modules/audio_conference_mixer/interface/audio_conference_mixer.h
index 29b957dcdfcc767ee1cd3189a6e92212235b3f03..b408b9324386e5a5cd79a5f7cb3cdafa44cb32fd 100644
--- a/webrtc/modules/audio_conference_mixer/interface/audio_conference_mixer.h
+++ b/webrtc/modules/audio_conference_mixer/interface/audio_conference_mixer.h
@@ -44,25 +44,25 @@ public:
 
     // Register/unregister a callback class for receiving the mixed audio.
     virtual int32_t RegisterMixedStreamCallback(
-        AudioMixerOutputReceiver& receiver) = 0;
+        AudioMixerOutputReceiver* receiver) = 0;
     virtual int32_t UnRegisterMixedStreamCallback() = 0;
 
     // Add/remove participants as candidates for mixing.
-    virtual int32_t SetMixabilityStatus(MixerParticipant& participant,
+    virtual int32_t SetMixabilityStatus(MixerParticipant* participant,

[Andrew MacDonald, 2015/08/26 15:56:01]

Looks like participant can be const?

[minyue-webrtc, 2015/08/27 11:31:15]

This will finally invoke operations (push, erase) in participant list, which is
a list<participant*>. push_back(const participant*) is not defined, and hence
const participant& cannot be passed down.

                                         bool mixable) = 0;
     // mixable is set to true if a participant is a candidate for mixing.
-    virtual int32_t MixabilityStatus(MixerParticipant& participant,
-                                     bool& mixable) = 0;
+    virtual int32_t MixabilityStatus(const MixerParticipant& participant,
+                                     bool* mixable) const = 0;

[Andrew MacDonald, 2015/08/26 15:56:01]

Can you have this return the bool instead?

[minyue-webrtc, 2015/08/27 11:31:15]

Yes, that sounds good.

 
     // Inform the mixer that the participant should always be mixed and not
     // count toward the number of mixed participants. Note that a participant
     // must have been added to the mixer (by calling SetMixabilityStatus())
     // before this function can be successfully called.
-    virtual int32_t SetAnonymousMixabilityStatus(MixerParticipant& participant,
-                                                 const bool mixable) = 0;
+    virtual int32_t SetAnonymousMixabilityStatus(
+        MixerParticipant* participant, bool mixable) = 0;
     // mixable is set to true if the participant is mixed anonymously.
-    virtual int32_t AnonymousMixabilityStatus(MixerParticipant& participant,
-                                              bool& mixable) = 0;
+    virtual int32_t AnonymousMixabilityStatus(
+        const MixerParticipant& participant, bool* mixable) const = 0;
 
     // Set the minimum sampling frequency at which to mix. The mixing algorithm
     // may still choose to mix at a higher samling frequency to avoid