Add STREAM_MP3 in GetSupportedStreamEncodings to unblock open media in browser...

Add STREAM_MP3 in GetSupportedStreamEncodings to unblock open media in browser before decoder is ready.

Bug: b:112162166
Change-Id: I7cbc3a753742ac9626877b8b76acc052328c90a1
Reviewed-on: https://chromium-review.googlesource.com/1164164Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Reviewed-by: Tao Wu <wutao@chromium.org>
Commit-Queue: Li Lin <llin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#581303}

chromeos/services/assistant/platform/audio_output_provider_impl.cc

@@ -181,6 +181,7 @@ AudioOutputProviderImpl::GetSupportedStreamEncodings() {
       assistant_client::OutputStreamEncoding::STREAM_PCM_S16,
       assistant_client::OutputStreamEncoding::STREAM_PCM_S32,
       assistant_client::OutputStreamEncoding::STREAM_PCM_F32,
+      assistant_client::OutputStreamEncoding::STREAM_MP3,
   };
 }
 
@@ -216,14 +217,20 @@ void AudioDeviceOwner::StartOnMainThread(
   DCHECK(!output_device_);
   DCHECK(main_thread_task_runner_->RunsTasksInCurrentSequence());
 
+  delegate_ = delegate;
   format_ = format;
+  // TODO(wutao): Remove this after supporting mp3 encoding.
+  if (format_.encoding == assistant_client::OutputStreamEncoding::STREAM_MP3) {
+    delegate_->OnEndOfStream();
+    return;
+  }
+
   audio_param_ = GetAudioParametersFromBufferFormat(format_);
 
   // |audio_fifo_| contains 3x the number of frames to render.
   audio_fifo_ = std::make_unique<media::AudioBlockFifo>(
       format.pcm_num_channels, audio_param_.frames_per_buffer(), 3);
   audio_data_.resize(GetBufferSizeInBytesFromBufferFormat(format_));
-  delegate_ = delegate;
   ScheduleFillLocked(base::TimeTicks::Now());
 
   // |connector| is null in unittest.