[chrome.displaySource][WiFi Display] Audio formats capability negotiation

extensions/renderer/api/display_source/wifi_display/wifi_display_media_manager.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "extensions/renderer/api/display_source/wifi_display/wifi_display_media_manager.h"
 
 #include "base/logging.h"
 #include "base/rand_util.h"
 #include "content/public/renderer/media_stream_api.h"
 
 namespace extensions {
 
 namespace {
 
 const char kErrorNoVideoFormatData[] =
     "Failed to get video format data from the given MediaStreamTrack object";
 const char kErrorSinkCannotPlayVideo[] =
     "The sink cannot play video from the given MediaStreamTrack object";
-
+const char kErrorSinkCannotPlayAudio[] =
+    "The sink cannot play audio from the given MediaStreamTrack object";
 }  // namespace
 
 WiFiDisplayMediaManager::WiFiDisplayMediaManager(
     const blink::WebMediaStreamTrack& video_track,
     const blink::WebMediaStreamTrack& audio_track,
     const ErrorCallback& error_callback)
   : video_track_(video_track),
     audio_track_(audio_track),
     error_callback_(error_callback) {
   DCHECK(!video_track.isNull() || !audio_track.isNull());
@@ skipping 184 matching lines @@
       capture_format, sink_supported_codecs, &optimal_video_format_)) {
     error_callback_.Run(kErrorSinkCannotPlayVideo);
     return false;
   }
 
   return true;
 }
 
 bool WiFiDisplayMediaManager::InitOptimalAudioFormat(
     const std::vector<wds::AudioCodec>& sink_codecs) {
-  NOTIMPLEMENTED();
+  for (const wds::AudioCodec& codec : sink_codecs) {
+    // MediaStreamTrack contains LPCM audio.
+    if (codec.format == wds::LPCM) {
+      optimal_audio_codec_ = codec;
+      // Picking a single mode.
+      wds::AudioModes optimal_mode;
+      if (codec.modes.test(wds::LPCM_44_1K_16B_2CH))
+        optimal_mode.set(wds::LPCM_44_1K_16B_2CH);
+      else
+        optimal_mode.set(wds::LPCM_48K_16B_2CH);
+      optimal_audio_codec_.modes = optimal_mode;
+      return true;
+    }
+  }
+  error_callback_.Run(kErrorSinkCannotPlayAudio);
   return false;
 }
 
 wds::AudioCodec WiFiDisplayMediaManager::GetOptimalAudioFormat() const {
-  NOTIMPLEMENTED();
-  return wds::AudioCodec();
+  return optimal_audio_codec_;
 }
 
 }  // namespace extensions