Bug 1220929 - RemotePageManager should let us get all ports for a browser. r=Mossop

--HG--
extra : commitid : KskXZGLHVfM
extra : rebase_source : ac92a506356bbb7a61a3b3dd8b9e7f4d107cfb2d

toolkit/modules/RemotePageManager.jsm

@@ -153,6 +153,10 @@ RemotePages.prototype = {
 
     this.listener.removeMessageListener(name, callback);
   },
+
+  portsForBrowser: function(browser) {
+    return [...this.messagePorts].filter(port => port.browser == browser);
+  },
 };