Fixing mono/stereo crash

BUG=467216

Review URL: https://codereview.chromium.org/1020683002

Cr-Commit-Position: refs/heads/master@{#321245}

components/audio_modem/audio_recorder_impl.cc

@@ -175,7 +175,7 @@ void AudioRecorderImpl::OnData(media::AudioInputStream* stream,
   // Buffer full, send it for processing.
   if (buffer_->frames() == buffer_frame_index_) {
     ProcessSamples(buffer_.Pass(), decode_callback_);
-    buffer_ = media::AudioBus::Create(kDefaultChannels, total_buffer_frames_);
+    buffer_ = media::AudioBus::Create(source->channels(), total_buffer_frames_);
     buffer_frame_index_ = 0;
 
     // Copy any remaining frames in the source to our buffer.

components/audio_modem/constants.cc

@@ -10,7 +10,6 @@ const int kDefaultRepetitions = 5;
 const float kDefaultSampleRate = 48000.0f;
 const int kDefaultBitsPerSample = 16;
 const float kDefaultCarrierFrequency = 18500.0f;
-const int kDefaultChannels = 2;
 const media::ChannelLayout kDefaultChannelLayout = media::CHANNEL_LAYOUT_STEREO;
 
 }  // namespace audio_modem

components/audio_modem/public/audio_modem_types.h

@@ -25,9 +25,8 @@ extern const float kDefaultSampleRate;
 extern const int kDefaultBitsPerSample;
 extern const float kDefaultCarrierFrequency;
 
-// The next two really need to be configurable since they don't need to be
-// consistent across platforms, or even playing/recording.
-extern const int kDefaultChannels;
+// This really needs to be configurable since it doesn't need
+// to be consistent across platforms, or even playing/recording.
 extern const media::ChannelLayout kDefaultChannelLayout;
 
 // Enum to represent the audio band (audible vs. ultrasound).