[Extensions Page] Add a listener on extension list for "hasExtensions" changing

chrome/browser/resources/extensions/extensions.js

Index: chrome/browser/resources/extensions/extensions.js
diff --git a/chrome/browser/resources/extensions/extensions.js b/chrome/browser/resources/extensions/extensions.js
index e094312bba88eb769323613216a95ca2a3c30158..f95e625223554fd7b7184470b5991df4247b3b9b 100644
--- a/chrome/browser/resources/extensions/extensions.js
+++ b/chrome/browser/resources/extensions/extensions.js
@@ -274,14 +274,24 @@ cr.define('extensions', function() {
           document.documentElement.classList.remove('loading');
         }, 0);
 
-        /** @const */
-        var hasExtensions = extensionList.getNumExtensions() != 0;
-        $('no-extensions').hidden = hasExtensions;
-        $('extension-list-wrapper').hidden = !hasExtensions;
+        extensionList.onExtensionCountChanged =
+            this.updateListVisibility_.bind(this);
+        this.updateListVisibility_();

[Dan Beam, 2015/04/27 16:17:05]

why does the |this| matter at all for this method?

       }.bind(this));
     },
 
     /**
+     * Updates the visibility of the extension list and "Boo..." message.
+     * @private
+     */
+    updateListVisibility_: function() {

[Dan Beam, 2015/04/27 16:17:05]

make this static

[Devlin, 2015/04/27 18:28:30]

Now, since this is a delegate method, I don't think this makes as much sense. 
Lemme know if you still want me to.

[Dan Beam, 2015/04/27 18:47:59]

fine as is

+      /** @const */
+      var hasExtensions = $('extension-settings-list').getNumExtensions() != 0;
+      $('no-extensions').hidden = hasExtensions;
+      $('extension-list-wrapper').hidden = !hasExtensions;
+    },
+
+    /**
      * Handles the Pack Extension button.
      * @param {Event} e Change event.
      * @private