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

chrome/browser/resources/extensions/extension_list.js

Index: chrome/browser/resources/extensions/extension_list.js
diff --git a/chrome/browser/resources/extensions/extension_list.js b/chrome/browser/resources/extensions/extension_list.js
index fe1cec3976b0da7f2f2fa13f2178b37c6cc06544..178e781406fbd9594c1ee75135d251deea00de68 100644
--- a/chrome/browser/resources/extensions/extension_list.js
+++ b/chrome/browser/resources/extensions/extension_list.js
@@ -248,10 +248,19 @@ cr.define('extensions', function() {
           case EventType.PREFS_CHANGED:
             if (eventData.extensionInfo)
               this.updateExtension_(eventData.extensionInfo);
+            if (eventData.event_type == EventType.INSTALLED &&
+                this.extensions_.length == 1 &&

[Dan Beam, 2015/04/23 18:01:38]

why length == 1?  can't we just call this every time?

[Devlin, 2015/04/23 18:27:31]

Sure.

+                this.onHasExtensionsChanged) {
+              this.onHasExtensionsChanged();
+            }
             break;
           case EventType.UNINSTALLED:
+            var index = this.getIndexOfExtension_(eventData.item_id);
+            this.extensions_.splice(index, 1);
             var childNode = $(eventData.item_id);
             childNode.parentNode.removeChild(childNode);
+            if (this.extensions_.length == 0 && this.onHasExtensionsChanged)
+              this.onHasExtensionsChanged();

[Dan Beam, 2015/04/23 18:01:38]

can't we just call this every time?

[Devlin, 2015/04/23 18:27:31]

Ditto.

             break;
           default:
             assertNotReached();
@@ -293,6 +302,19 @@ cr.define('extensions', function() {
       return this.extensions_.length;
     },
 
+    /**
+     * @param {string} id The id of the extension.
+     * @return {number} The index of the extension with the given id.
+     * @private
+     */
+    getIndexOfExtension_: function(id) {
+      for (var i = 0; i < this.extensions_.length; ++i) {
+        if (this.extensions_[i].id == id)
+          return i;
+      }
+      return -1;
+    },
+
     getIdQueryParam_: function() {
       return parseQueryParams(document.location)['id'];
     },
@@ -1030,13 +1052,7 @@ cr.define('extensions', function() {
      * @private
      */
     updateExtension_: function(extension) {
-      var currIndex = -1;
-      for (var i = 0; i < this.extensions_.length; ++i) {
-        if (this.extensions_[i].id == extension.id) {
-          currIndex = i;
-          break;
-        }
-      }
+      var currIndex = this.getIndexOfExtension_(extension.id);
       if (currIndex != -1) {
         // If there is a current version of the extension, update it with the
         // new version.