[Extensions] Make chrome://extensions use developerPrivate for unpacked loading

chrome/browser/resources/extensions/extension_loader.js

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 cr.define('extensions', function() {
   'use strict';
 
   /**
    * Construct an ExtensionLoadError around the given |div|.
    * @param {HTMLDivElement} div The HTML div for the extension load error.
@@ skipping 168 matching lines @@
      * @private
      */
     this.loadError_ = new ExtensionLoadError(
         /** @type {HTMLDivElement} */($('extension-load-error')));
   }
 
   cr.addSingletonGetter(ExtensionLoader);
 
   ExtensionLoader.prototype = {
     /**
+     * Whether or not we are currently loading an unpacked extension.
+     * @private {boolean}
+     */
+    isLoading_: false,
+
+    /**
      * Begin the sequence of loading an unpacked extension. If an error is
      * encountered, this object will get notified via notifyFailed().
      */
     loadUnpacked: function() {
-      chrome.send('extensionLoaderLoadUnpacked');
+      if (this.isLoading_)  // Only one running load at a time.
+        return;
+      this.isLoading_ = true;
+      chrome.developerPrivate.loadUnpacked({failQuietly: true}, function() {
+        // Check lastError to avoid the log, but don't do anything with it -
+        // error-handling is done on the C++ side.
+        var lastError = chrome.runtime.lastError;
+        this.isLoading_ = false;
+      }.bind(this));
     },
 
     /**
      * Notify the ExtensionLoader that loading an unpacked extension failed.
      * Add the failure to failures_ and show the ExtensionLoadError.
      * @param {Array<Object>} failures Array of failures containing paths,
      *     errors, and manifests.
      */
     notifyFailed: function(failures) {
       this.loadError_.add_(failures);
     },
   };
 
   /**
    * A static forwarding function for ExtensionLoader.notifyFailed.
    * @param {Array<Object>} failures Array of failures containing paths,
    *     errors, and manifests.
    * @see ExtensionLoader.notifyFailed
    */
   ExtensionLoader.notifyLoadFailed = function(failures) {
     ExtensionLoader.getInstance().notifyFailed(failures);
   };
 
   return {
     ExtensionLoader: ExtensionLoader
   };
 });