Fix CPU spin on joining rooms

Ratelimit roomheader's updates and move some other things into
rate limited functions.

src/components/structures/RoomView.js

@@ -573,18 +573,17 @@ module.exports = React.createClass({
             return;
         }
 
-        if (this.props.ConferenceHandler &&
-            member.userId === this.props.ConferenceHandler.getConferenceUserIdForRoom(member.roomId)) {
-            this._updateConfCallNotification();
-        }
-
         this._updateRoomMembers();
     },
 
     // rate limited because a power level change will emit an event for every
     // member in the room.
     _updateRoomMembers: new rate_limited_func(function() {
-        // a member state changed in this room, refresh the tab complete list
+        // a member state changed in this room
+        // refresh, the conf call notification state
+        this._updateConfCallNotification();
+
+        // refresh the tab complete list
         this.tabComplete.loadEntries(this.state.room);
         this._updateAutoComplete();
 

src/components/views/rooms/RoomHeader.js

@@ -21,6 +21,7 @@ var sdk = require('../../../index');
 var MatrixClientPeg = require('../../../MatrixClientPeg');
 var Modal = require("../../../Modal");
 var dis = require("../../../dispatcher");
+var rate_limited_func = require('../../../ratelimitedfunc');
 
 var linkify = require('linkifyjs');
 var linkifyElement = require('linkifyjs/element');
@@ -85,9 +86,13 @@ module.exports = React.createClass({
         }
 
         // redisplay the room name, topic, etc.
-        this.forceUpdate();
+        this._rateLimitedUpdate();
     },
 
+    _rateLimitedUpdate: new rate_limited_func(function() {
+        this.forceUpdate();
+    }, 500),
+
     _onRoomNameChange: function(room) {
         this.forceUpdate();
     },