Add support for echoCancellation and deviceId to MediaStreamTrack.getSettings

content/renderer/media/user_media_client_impl.cc

Index: content/renderer/media/user_media_client_impl.cc
diff --git a/content/renderer/media/user_media_client_impl.cc b/content/renderer/media/user_media_client_impl.cc
index 96ebd7bdfa3e904ab5ee720b51fc1a33f03277a6..4ba10f4c03ca964c72959dd2cb2a1c192329b539 100644
--- a/content/renderer/media/user_media_client_impl.cc
+++ b/content/renderer/media/user_media_client_impl.cc
@@ -232,6 +232,15 @@ bool IsValidVideoContentSource(const std::string& source) {
          source == kMediaStreamSourceScreen;
 }
 
+void SetHardwareEchoCancellationSetting(blink::WebMediaStreamSource* source) {

[hbos_chromium, 2017/07/04 15:26:49]

Should this be generalized and/or renamed, e.g. SurfaceAudioParamsSettings or
SurfaceHardwareEchoCancellationSetting?
"Set" makes it sound like the value is always updated to reflect the hw value,
when in truth it only sets it to true if it has that effect. It could already be
true due to sw. Please add a comment.

Is this logic specific to ECHO_CANCELLER or would the code look the same for any
AudioParameters that are of interest (e.g. set if true, leave old value
otherwise)?

[Guido Urdaneta, 2017/07/05 09:23:36]

This would probably be the place for future settings that depend on parameters.
However, I prefer to wait until we implement those features before renaming to a
more generic name.
Renamed to SurfaceHardwareEchoCancellationSetting for now.

+  MediaStreamAudioSource* source_impl =
+      static_cast<MediaStreamAudioSource*>(source->GetExtraData());
+  media::AudioParameters params = source_impl->GetAudioParameters();
+  if (params.IsValid() &&
+      (params.effects() & media::AudioParameters::ECHO_CANCELLER))
+    source->SetEchoCancellation(true);
+}
+
 static int g_next_request_id = 0;
 
 }  // namespace
@@ -968,18 +977,23 @@ blink::WebMediaStreamSource UserMediaClientImpl::InitializeAudioSourceObject(
       &UserMediaClientImpl::OnAudioSourceStartedOnAudioThread,
       base::ThreadTaskRunnerHandle::Get(), weak_factory_.GetWeakPtr());
 
-  MediaStreamAudioSource* const audio_source =
-      CreateAudioSource(device, constraints, source_ready);
+  bool has_sw_echo_cancellation = false;
+  MediaStreamAudioSource* const audio_source = CreateAudioSource(
+      device, constraints, source_ready, &has_sw_echo_cancellation);
   audio_source->SetStopCallback(base::Bind(
       &UserMediaClientImpl::OnLocalSourceStopped, weak_factory_.GetWeakPtr()));
   source.SetExtraData(audio_source);  // Takes ownership.
+  // If the hardware has echo cancellation, the value is updated in
+  // CreateAudioTracks(), after the track has started.

[hbos_chromium, 2017/07/04 15:26:48]

Could you clarify that the reason we don't set it here is because we don't know
that yet.

[Guido Urdaneta, 2017/07/05 09:23:37]

Done.

+  source.SetEchoCancellation(has_sw_echo_cancellation);
   return source;
 }
 
 MediaStreamAudioSource* UserMediaClientImpl::CreateAudioSource(
     const StreamDeviceInfo& device,
     const blink::WebMediaConstraints& constraints,
-    const MediaStreamSource::ConstraintsCallback& source_ready) {
+    const MediaStreamSource::ConstraintsCallback& source_ready,
+    bool* has_sw_echo_cancellation) {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   DCHECK(current_request_info_);
   // If the audio device is a loopback device (for screen capture), or if the
@@ -993,6 +1007,7 @@ MediaStreamAudioSource* UserMediaClientImpl::CreateAudioSource(
   if (IsScreenCaptureMediaType(device.device.type) ||
       !MediaStreamAudioProcessor::WouldModifyAudio(
           audio_processing_properties)) {
+    *has_sw_echo_cancellation = false;
     return new LocalMediaStreamAudioSource(RenderFrameObserver::routing_id(),
                                            device, source_ready);
   }
@@ -1002,6 +1017,8 @@ MediaStreamAudioSource* UserMediaClientImpl::CreateAudioSource(
   ProcessedLocalAudioSource* source = new ProcessedLocalAudioSource(
       RenderFrameObserver::routing_id(), device, audio_processing_properties,
       source_ready, dependency_factory_);
+  *has_sw_echo_cancellation =
+      audio_processing_properties.enable_sw_echo_cancellation;
   return source;
 }
 
@@ -1070,6 +1087,7 @@ void UserMediaClientImpl::CreateAudioTracks(
         overridden_audio_array[i], constraints, &is_pending);
     (*webkit_tracks)[i].Initialize(source);
     current_request_info_->StartAudioTrack((*webkit_tracks)[i], is_pending);
+    SetHardwareEchoCancellationSetting(&source);

[hbos_chromium, 2017/07/04 15:26:48]

Add a comment saying the source's current value reflects if it has sw and it is
updated if we have hw (but the old value doesn't change otherwise)... if this
isn't clear from function name change.

[Guido Urdaneta, 2017/07/05 09:23:36]

Done.

   }
 }