Improves stereo/mono audio support on Android

webrtc/modules/audio_device/android/opensles_player.cc

Index: webrtc/modules/audio_device/android/opensles_player.cc
diff --git a/webrtc/modules/audio_device/android/opensles_player.cc b/webrtc/modules/audio_device/android/opensles_player.cc
index 513f8233f855e050152a2a36189df82036be7282..3a40bf477992698795e58cbd3957b87b3fa5a41c 100644
--- a/webrtc/modules/audio_device/android/opensles_player.cc
+++ b/webrtc/modules/audio_device/android/opensles_player.cc
@@ -79,6 +79,11 @@ OpenSLESPlayer::~OpenSLESPlayer() {
 int OpenSLESPlayer::Init() {
   ALOGD("Init%s", GetThreadInfo().c_str());
   RTC_DCHECK(thread_checker_.CalledOnValidThread());
+  if (audio_parameters_.channels() == 2) {
+    // TODO(henrika): FineAudioBuffer needs more work to support stereo.
+    ALOGE("OpenSLESPlayer does not support stereo");
+    return -1;
+  }
   return 0;
 }