Removes automatic setting of COMM mode in WebRTC

talk/examples/android/src/org/appspot/apprtc/AppRTCAudioManager.java

 /*
  * libjingle
  * Copyright 2014 Google Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  *  1. Redistributions of source code must retain the above copyright notice,
  *     this list of conditions and the following disclaimer.
  *  2. Redistributions in binary form must reproduce the above copyright notice,
@@ skipping 133 matching lines @@
 
     // Store current audio state so we can restore it when close() is called.
     savedAudioMode = audioManager.getMode();
     savedIsSpeakerPhoneOn = audioManager.isSpeakerphoneOn();
     savedIsMicrophoneMute = audioManager.isMicrophoneMute();
 
     // Request audio focus before making any device switch.
     audioManager.requestAudioFocus(null, AudioManager.STREAM_VOICE_CALL,
         AudioManager.AUDIOFOCUS_GAIN_TRANSIENT);
 
-    // Start by setting RINGTONE as default audio mode. The native WebRTC
-    // audio layer will switch to COMMUNICATION mode when the first streaming
-    // session starts and return to RINGTONE mode when all streaming stops.
-    audioManager.setMode(AudioManager.MODE_RINGTONE);
+    // Start by setting MODE_IN_COMMUNICATION as default audio mode. It is
+    // required to be in this mode when playout and/or recording starts for
+    // best possible VoIP performance.
+    // TODO(henrika): we migh want to start with RINGTONE mode here instead.
+    audioManager.setMode(AudioManager.MODE_IN_COMMUNICATION);
 
     // Always disable microphone mute during a WebRTC call.
     setMicrophoneMute(false);
 
     // Do initial selection of audio device. This setting can later be changed
     // either by adding/removing a wired headset or by covering/uncovering the
     // proximity sensor.
     updateAudioDeviceState(hasWiredHeadset());
 
     // Register receiver for broadcast intents related to adding/removing a
@@ skipping 195 matching lines @@
       Log.e(TAG, "Invalid device list");
     }
 
     if (onStateChangeListener != null) {
       // Run callback to notify a listening client. The client can then
       // use public getters to query the new state.
       onStateChangeListener.run();
     }
   }
 }