Avoid proxy thread hops for reading const properties.

This bypasses the proxy for the following properties:
* MediaStream::id()
* AudioTrack::kind() and AudioTrack::id()
* VideoTrack::kind() and VideoTrack::id()
* RtpReceiver::media_type() and RtpReceiver::id()
* RtpSender::media_type() and RtpSender::id()
* VideoTrackSource::remote() and VideoTrackSource::is_screencast()
* RtpTransceiver::media_type()

Bug: webrtc:11923
Change-Id: If7edea1781f778af3775515fc4af9a9e151c8103
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/183767
Reviewed-by: Chen Xing <chxg@google.com>
Commit-Queue: Tommi <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32071}
diff --git a/api/rtp_receiver_interface.h b/api/rtp_receiver_interface.h
index a15864e..786ea3a 100644
--- a/api/rtp_receiver_interface.h
+++ b/api/rtp_receiver_interface.h
@@ -128,8 +128,8 @@
 PROXY_CONSTMETHOD0(std::vector<std::string>, stream_ids)
 PROXY_CONSTMETHOD0(std::vector<rtc::scoped_refptr<MediaStreamInterface>>,
                    streams)
-PROXY_CONSTMETHOD0(cricket::MediaType, media_type)
-PROXY_CONSTMETHOD0(std::string, id)
+BYPASS_PROXY_CONSTMETHOD0(cricket::MediaType, media_type)
+BYPASS_PROXY_CONSTMETHOD0(std::string, id)
 PROXY_CONSTMETHOD0(RtpParameters, GetParameters)
 PROXY_METHOD1(void, SetObserver, RtpReceiverObserverInterface*)
 PROXY_METHOD1(void, SetJitterBufferMinimumDelay, absl::optional<double>)