Improves stereo/mono audio support on Android

webrtc/modules/audio_device/android/opensles_recorder.cc

 /*
  *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 58 matching lines @@
   DestroyAudioRecorder();
   engine_ = nullptr;
   RTC_DCHECK(!engine_);
   RTC_DCHECK(!recorder_);
   RTC_DCHECK(!simple_buffer_queue_);
 }
 
 int OpenSLESRecorder::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("OpenSLESRecorder does not support stereo");
+    return -1;
+  }
   return 0;
 }
 
 int OpenSLESRecorder::Terminate() {
   ALOGD("Terminate%s", GetThreadInfo().c_str());
   RTC_DCHECK(thread_checker_.CalledOnValidThread());
   StopRecording();
   return 0;
 }
 
@@ skipping 330 matching lines @@
   SLAndroidSimpleBufferQueueState state = GetBufferQueueState();
   ALOGD("state.count:%d state.index:%d", state.count, state.index);
 }
 
 SLuint32 OpenSLESRecorder::GetBufferCount() {
   SLAndroidSimpleBufferQueueState state = GetBufferQueueState();
   return state.count;
 }
 
 }  // namespace webrtc