message: Remove Invoke from BaseChannel::SetPayloadTypeDemuxingEnabled
  The Invoke() isn't necessary as the method is always called on the
  correct thread (now enforced with a DCHECK).
  Cr-Commit-Position: refs/heads/master@{#33899}
diff: @@ -326,11 +326,9 @@ void BaseChannel::SetContent_s(const MediaContentDescription* content,
  }
  bool BaseChannel::SetPayloadTypeDemuxingEnabled(bool enabled) {
  - TRACE_EVENT0("webrtc", "BaseChannel::SetPayloadTypeDemuxingEnabled");
  - return InvokeOnWorker<bool>(RTC_FROM_HERE, [this, enabled] {
  RTC_DCHECK_RUN_ON(worker_thread());
  + TRACE_EVENT0("webrtc", "BaseChannel::SetPayloadTypeDemuxingEnabled");
  return SetPayloadTypeDemuxingEnabled_w(enabled);
  - });
  }
  bool BaseChannel::IsReadyToReceiveMedia_w() const {
  