Move audio frame memory handling inside AudioMixer.

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 500bb7862e5defe2b9fd906c057c6cf60fec3087..df14b3b469e31b4049806cd540b72cc87662bb9f 100644
--- a/webrtc/modules/audio_mixer/audio_mixer_impl.h
+++ b/webrtc/modules/audio_mixer/audio_mixer_impl.h
@@ -29,15 +29,22 @@ typedef std::vector<AudioFrame*> AudioFrameList;
 
 class AudioMixerImpl : public AudioMixer {
  public:
-  struct SourceStatus {
-    SourceStatus(Source* audio_source, bool is_mixed, float gain)
-        : audio_source(audio_source), is_mixed(is_mixed), gain(gain) {}
+  struct SourceStatusWithFrame {
+    SourceStatusWithFrame(Source* audio_source, bool is_mixed, float gain)
+        : audio_source(audio_source),
+          is_mixed(is_mixed),
+          gain(gain),
+          audio_frame() {}
     Source* audio_source = nullptr;
     bool is_mixed = false;
     float gain = 0.0f;
+
+    // A frame that will be passed to audio_source->GetAudioFrameWithInfo.
+    AudioFrame audio_frame{};
   };
 
-  typedef std::vector<SourceStatus> SourceStatusList;
+  typedef std::vector<std::unique_ptr<SourceStatusWithFrame>>
+      SourceStatusWithFrameList;
 
   // AudioProcessing only accepts 10 ms frames.
   static const int kFrameDurationInMs = 10;
@@ -77,9 +84,10 @@ class AudioMixerImpl : public AudioMixer {
   // Add/remove the MixerAudioSource to the specified
   // MixerAudioSource list.
   bool AddAudioSourceToList(Source* audio_source,
-                            SourceStatusList* audio_source_list) const;
-  bool RemoveAudioSourceFromList(Source* remove_audio_source,
-                                 SourceStatusList* audio_source_list) const;
+                            SourceStatusWithFrameList* audio_source_list) const;
+  bool RemoveAudioSourceFromList(
+      Source* remove_audio_source,
+      SourceStatusWithFrameList* audio_source_list) const;
 
   bool LimitMixedAudio(AudioFrame* mixed_audio) const;
 
@@ -91,7 +99,8 @@ class AudioMixerImpl : public AudioMixer {
   size_t sample_size_ ACCESS_ON(&thread_checker_);
 
   // List of all audio sources. Note all lists are disjunct
-  SourceStatusList audio_source_list_ GUARDED_BY(crit_);  // May be mixed.
+  SourceStatusWithFrameList audio_source_list_
+      GUARDED_BY(crit_);  // May be mixed.
 
   // Determines if we will use a limiter for clipping protection during
   // mixing.