Bug 1531811 - Part 1: Remove onremovestream from RTCPeerConnection. r=smaug,jib

Differential Revision: https://phabricator.services.mozilla.com/D23210

--HG--
extra : moz-landing-system : lando

dom/webidl/RTCPeerConnection.webidl

@@ -163,7 +163,6 @@ interface RTCPeerConnection : EventTarget  {
   attribute EventHandler onaddstream; // obsolete
   attribute EventHandler onaddtrack;  // obsolete
   attribute EventHandler ontrack;     // replaces onaddtrack and onaddstream.
-  attribute EventHandler onremovestream;
   attribute EventHandler oniceconnectionstatechange;
   attribute EventHandler onicegatheringstatechange;