[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 35eea3414ddc7a06f35e288132525dddf6acdeb4..8067aa1f00d6f351fdfd4cb2530d8760b4d4ebc6 100644
--- a/chrome/browser/resources/extensions/extension_list.js
+++ b/chrome/browser/resources/extensions/extension_list.js
@@ -235,6 +235,9 @@ cr.define('extensions', function() {
       /** @private {!Array<ExtensionInfo>} */
       this.extensions_ = [];
 
+      /** @type {?function()} */
+      this.onExtensionCountChanged = null;

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

why does this need to ever be assigned/created dynamically?

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

Per offline conversation, extracted this into a delegate.

+
       /**
        * |loadFinished| should be used for testing purposes and will be
        * fulfilled when this list has finished loading the first time.
@@ -260,12 +263,20 @@ cr.define('extensions', function() {
               this.updateExtension_(eventData.extensionInfo);
             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);
             break;
           default:
             assertNotReached();
         }
+
+        if ((eventData.event_type == EventType.INSTALLED ||
+             eventData.event_type == EventType.UNINSTALLED) &&
+            this.onExtensionCountChanged) {
+          this.onExtensionCountChanged();
+        }
       }.bind(this));
     },
 
@@ -334,6 +345,19 @@ 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'];
     },
@@ -1063,13 +1087,7 @@ 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.