Conversation.notify(): introduce a promise to track completion

FREEBIE

js/models/conversations.js

@@ -815,16 +815,19 @@
 
     notify: function(message) {
         if (!message.isIncoming()) {
-            return;
+            return Promise.resolve();
         }
         if (window.isOpen() && window.isFocused()) {
-            return;
+            return Promise.resolve();
         }
+
         window.drawAttention();
         var sender = ConversationController.create({
             id: message.get('source'), type: 'private'
         });
         var conversationId = this.id;
+
+        return new Promise(function(resolve, reject) {
             sender.fetch().then(function() {
                 sender.getNotificationIcon().then(function(iconUrl) {
                     console.log('adding notification');
@@ -836,7 +839,10 @@
                         conversationId : conversationId,
                         messageId      : message.id
                     });
-            });
+
+                    return resolve();
+                }, reject);
+            }, reject);
         });
     },
     hashCode: function() {