Fix for "Android audio playout doesn't support non-call media stream"

BUG=webrtc:4767
R=magjed@webrtc.org

Review URL: https://codereview.webrtc.org/1419693004 .

Cr-Commit-Position: refs/heads/master@{#10435}

webrtc/modules/audio_device/android/opensles_player.h

@@ -130,6 +130,20 @@ class OpenSLESPlayer {
   // AudioManager.
   const AudioParameters audio_parameters_;
 
+  // Contains the stream type provided to this class at construction by the
+  // AudioManager. Possible input values are:
+  //  - AudioManager.STREAM_VOICE_CALL = 0
+  //  - AudioManager.STREAM_RING = 2
+  //  - AudioManager.STREAM_MUSIC = 3
+  // These value are mapped to the corresponding audio playback stream type
+  // values in the "OpenSL ES domain":
+  // - SL_ANDROID_STREAM_VOICE <=> STREAM_VOICE_CALL (0)
+  // - SL_ANDROID_STREAM_RING <=> STREAM_RING (2)
+  // - SL_ANDROID_STREAM_MEDIA <=> STREAM_MUSIC (3)
+  // when creating the audio player. See SLES/OpenSLES_AndroidConfiguration.h
+  // for details.
+  const int stream_type_;
+
   // Raw pointer handle provided to us in AttachAudioBuffer(). Owned by the
   // AudioDeviceModuleImpl class and called by AudioDeviceModuleImpl::Create().
   AudioDeviceBuffer* audio_device_buffer_;