Do notifications after message edits.

If a message edit causes a message to become notifiable, we send
a notification to the user, but only if they haven't had any previous
notifications for this message.

(imported from commit cee854de2d42c31a7352a350f79490caf94b613c)

static/js/notifications.js

@@ -321,6 +321,13 @@ function message_is_notifiable(message) {
     if (message.sent_by_me) {
         return false;
     }
+
+    // If a message is edited multiple times, we want to err on the side of
+    // not spamming notifications.
+    if (message.notification_sent) {
+        return false;
+    }
+
     // @-mentions take precent over muted-ness. See Trac #1929
     if (exports.speaking_at_me(message)) {
         return true;
@@ -362,6 +369,8 @@ exports.received_messages = function (messages) {
             return;
         }
 
+        message.notification_sent = true;
+
         if (page_params.desktop_notifications_enabled &&
             browser_desktop_notifications_on()) {
             process_notification({message: message, webkit_notify: true});

static/js/zulip.js

@@ -761,6 +761,7 @@ function update_messages(events) {
         msg.last_edit_timestamp = event.edit_timestamp;
         delete msg.last_edit_timestr;
 
+        notifications.received_messages([msg]);
         alert_words.process_message(msg);
     });