Bug 597644: feed button/menuitem isn't updated properly on back/forward navigation, r=dao, a=blocking

--HG--
extra : rebase_source : 13b67ff4b345902fb7f88dfbe875674462374cd6

browser/base/content/browser.js

@@ -6705,6 +6705,8 @@ var FeedHandler = {
    * a page is loaded or the user switches tabs to a page that has feeds.
    */
   updateFeeds: function() {
+    clearTimeout(this._updateFeedTimeout);
+
     var feeds = gBrowser.selectedBrowser.feeds;
     var haveFeeds = feeds && feeds.length > 0;
 
@@ -6742,6 +6744,15 @@ var FeedHandler = {
       browserForLink.feeds = [];
 
     browserForLink.feeds.push({ href: link.href, title: link.title });
+
+    // If this addition was for the current browser, update the UI. For
+    // background browsers, we'll update on tab switch.
+    if (browserForLink == gBrowser.selectedBrowser) {
+      // Batch updates to avoid updating the UI for multiple onLinkAdded events
+      // fired within 100ms of each other.
+      clearTimeout(this._updateFeedTimeout);
+      this._updateFeedTimeout = setTimeout(this.updateFeeds.bind(this), 100);
+    }
   }
 };