Change the default rtcp mux policy from negotiate to require.

content/renderer/media/rtc_peer_connection_handler.cc

Index: content/renderer/media/rtc_peer_connection_handler.cc
diff --git a/content/renderer/media/rtc_peer_connection_handler.cc b/content/renderer/media/rtc_peer_connection_handler.cc
index b19e92ba514a1643d7560773e071f269218d2bc4..edd41452f52937c66919478837471909269f9c4f 100644
--- a/content/renderer/media/rtc_peer_connection_handler.cc
+++ b/content/renderer/media/rtc_peer_connection_handler.cc
@@ -1396,12 +1396,6 @@ bool RTCPeerConnectionHandler::updateICE(
   return native_peer_connection_->UpdateIce(config.servers);
 }
 
-void RTCPeerConnectionHandler::logSelectedRtcpMuxPolicy(
-    blink::RtcpMuxPolicy selectedRtcpMuxPolicy) {
-  UMA_HISTOGRAM_ENUMERATION("WebRTC.PeerConnection.SelectedRtcpMuxPolicy",
-                            selectedRtcpMuxPolicy, blink::RtcpMuxPolicyMax);
-}
-
 bool RTCPeerConnectionHandler::addICECandidate(
     const blink::WebRTCVoidRequest& request,
     const blink::WebRTCICECandidate& candidate) {