Add <a is="action-link">, a web component extension of <a> for in-page actions.

chrome/browser/resources/extensions/extensions.js

 // Copyright (c) 2012 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.
 
 <include src="../uber/uber_utils.js">
 <include src="extension_code.js">
 <include src="extension_commands_overlay.js">
 <include src="extension_error_overlay.js">
 <include src="extension_focus_manager.js">
 <include src="extension_list.js">
@@ skipping 177 matching lines @@
 
       extensions.ExtensionFocusManager.getInstance().initialize();
 
       var path = document.location.pathname;
       if (path.length > 1) {
         // Skip starting slash and remove trailing slash (if any).
         var overlayName = path.slice(1).replace(/\/$/, '');
         if (overlayName == 'configureCommands')
           this.showExtensionCommandsConfigUi_();
       }
-
-      preventDefaultOnPoundLinkClicks();  // From webui/js/util.js.
     },
 
     /**
      * Updates the Chrome Apps and Extensions Developer Tools promotion's
      * visibility.
      * @private
      */
     updatePromoVisibility_: function() {
       var extensionSettings = $('extension-settings');
       var visible = extensionSettings.classList.contains('dev-mode') &&
@@ skipping 247 matching lines @@
 
   // Export
   return {
     ExtensionSettings: ExtensionSettings
   };
 });
 
 window.addEventListener('load', function(e) {
   extensions.ExtensionSettings.getInstance().initialize();
 });