Use to-device events for key sharing

Synapse now supports out-of-band messages, so use them instead of sending the
key-sharing messages in-band.

lib/client.js

@@ -144,7 +144,6 @@ function MatrixClient(opts) {
     this._peekSync = null;
     this._isGuest = false;
     this._ongoingScrollbacks = {};
-    this._txnCtr = 0;
     this.timelineSupport = Boolean(opts.timelineSupport);
     this.urlPreviewCache = {};
 
@@ -424,6 +423,12 @@ function setupCryptoEventHandler(client) {
     });
     client.on("RoomMember.membership",
               client._crypto.onRoomMembership.bind(client._crypto));
+
+    client.on("toDeviceEvent", function(event) {
+        if (event.getType() == "m.room_key") {
+            client._crypto.onRoomKeyEvent(event);
+        }
+    });
 }
 
 function onCryptoEvent(client, event) {
@@ -438,20 +443,6 @@ function onCryptoEvent(client, event) {
     }
 }
 
-/**
- * handle a room key event
- *
- * @private
- *
- * @param {MatrixEvent} event
- */
-MatrixClient.prototype._onRoomKeyEvent = function(event) {
-    if (!this._crypto) {
-        return;
-    }
-    this._crypto.onRoomKeyEvent(event);
-};
-
 /**
  * Enable end-to-end encryption for a room.
  * @param {string} roomId The room ID to enable encryption in.
@@ -820,7 +811,7 @@ MatrixClient.prototype.sendEvent = function(roomId, eventType, content, txnId,
     if (utils.isFunction(txnId)) { callback = txnId; txnId = undefined; }
 
     if (!txnId) {
-        txnId = "m" + new Date().getTime() + "." + (this._txnCtr++);
+        txnId = this.makeTxnId();
     }
 
     // we always construct a MatrixEvent when sending because the store and
@@ -921,11 +912,13 @@ function _updatePendingEventStatus(room, event, newStatus) {
 }
 
 function _sendEventHttpRequest(client, event) {
+    var txnId = event._txnId ? event._txnId : client.makeTxnId();
+
     var pathParams = {
         $roomId: event.getRoomId(),
         $eventType: event.getWireType(),
         $stateKey: event.getStateKey(),
-        $txnId: event._txnId ? event._txnId : new Date().getTime()
+        $txnId: txnId,
     };
 
     var path;
@@ -2663,13 +2656,6 @@ function _PojoToMatrixEventMapper(client) {
             clearData = _decryptMessage(client, plainOldJsObject);
         }
         var matrixEvent = new MatrixEvent(plainOldJsObject, clearData);
-
-        // XXXX massive hack to deal with the fact that megolm keys are in the
-        // room for now, and we need to handle them before attempting to
-        // decrypt the following megolm messages.
-        if (matrixEvent.getType() == "m.room_key") {
-            client._onRoomKeyEvent(matrixEvent);
-        }
         return matrixEvent;
     }
     return mapper;