downloads: put [column-type] in HTML template instead of JS.

chrome/browser/resources/downloads/focus_row.js

 // Copyright 2015 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('downloads', function() {
   /**
    * Provides an implementation for a single column grid.
    * @constructor
    * @extends {cr.ui.FocusRow}
    */
   function FocusRow() {}
 
   /**
    * Decorates |focusRow| so that it can be treated as a FocusRow.
    * @param {Element} focusRow The element that has all the columns represented
    *     by |itemView|.
    * @param {!downloads.ItemView} itemView The item view this row cares about.
    * @param {Node} boundary Focus events are ignored outside of this node.
    */
   FocusRow.decorate = function(focusRow, itemView, boundary) {
     focusRow.__proto__ = FocusRow.prototype;
     focusRow.decorate(boundary);
-
-    // Add all clickable elements as a row into the grid.
-    focusRow.addElementIfFocusable_(itemView.fileLink, 'name');
-    focusRow.addElementIfFocusable_(itemView.srcUrl, 'url');
-    focusRow.addElementIfFocusable_(itemView.show, 'show');
-    focusRow.addElementIfFocusable_(itemView.retry, 'retry');
-    focusRow.addElementIfFocusable_(itemView.pause, 'pause');
-    focusRow.addElementIfFocusable_(itemView.resume, 'resume');
-    focusRow.addElementIfFocusable_(itemView.safeRemove, 'remove');
-    focusRow.addElementIfFocusable_(itemView.cancel, 'cancel');
-    focusRow.addElementIfFocusable_(itemView.restore, 'save');
-    focusRow.addElementIfFocusable_(itemView.save, 'save');
-    focusRow.addElementIfFocusable_(itemView.dangerRemove, 'discard');
-    focusRow.addElementIfFocusable_(itemView.discard, 'discard');
-    focusRow.addElementIfFocusable_(itemView.controlledBy, 'extension');
+    focusRow.addFocusableElements_();
   };
 
   FocusRow.prototype = {
     __proto__: cr.ui.FocusRow.prototype,
 
     /** @override */
     getEquivalentElement: function(element) {
       if (this.focusableElements.indexOf(element) > -1)
         return assert(element);
 
       // All elements default to another element with the same type.
       var columnType = element.getAttribute('column-type');
       var equivalent = this.querySelector('[column-type=' + columnType + ']');
 
       if (this.focusableElements.indexOf(equivalent) < 0) {
+        equivalent = null;
         var equivalentTypes =
             ['show', 'retry', 'pause', 'resume', 'remove', 'cancel'];
         if (equivalentTypes.indexOf(columnType) != -1) {
           var allTypes = equivalentTypes.map(function(type) {
             return '[column-type=' + type + ']:not([hidden])';
           }).join(', ');
           equivalent = this.querySelector(allTypes);
         }
       }
 
       // Return the first focusable element if no equivalent element is found.
       return assert(equivalent || this.focusableElements[0]);
     },
 
-    /**
-     * @param {Element} element The element that should be added.
-     * @param {string} type The column type to use for the element.
-     * @private
-     */
-    addElementIfFocusable_: function(element, type) {
-      if (this.shouldFocus_(element)) {
-        this.addFocusableElement(element);
-        element.setAttribute('column-type', type);
+    /** @private */
+    addFocusableElements_: function() {
+      var possiblyFocusableElements = this.querySelectorAll('[column-type]');
+      for (var i = 0; i < possiblyFocusableElements.length; ++i) {
+        var possiblyFocusableElement = possiblyFocusableElements[i];
+        if (this.shouldFocus_(possiblyFocusableElement))
+          this.addFocusableElement(possiblyFocusableElement);
       }
     },
 
     /**
      * Determines if element should be focusable.
      * @param {Element} element
      * @return {boolean}
      * @private
      */
     shouldFocus_: function(element) {
       if (!element)
         return false;
 
       // Hidden elements are not focusable.
       var style = window.getComputedStyle(element);
       if (style.visibility == 'hidden' || style.display == 'none')
         return false;
 
       // Verify all ancestors are focusable.
       return !element.parentElement || this.shouldFocus_(element.parentElement);
     },
   };
 
   return {FocusRow: FocusRow};
 });