MD Settings: adjust iron-list focus row behaviors.

ui/webui/resources/js/cr/ui/focus_row.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('cr.ui', function() {
   /**
    * A class to manage focus between given horizontally arranged elements.
    *
    * Pressing left cycles backward and pressing right cycles forward in item
    * order. Pressing Home goes to the beginning of the list and End goes to the
@@ skipping 87 matching lines @@
      * Example: an (X) button might be 'delete' or 'close'.
      *
      * When FocusRow is used within a FocusGrid, these types are used to
      * determine equivalent controls when Up/Down are pressed to change rows.
      *
      * Another example: mutually exclusive controls that hide eachother on
      * activation (i.e. Play/Pause) could use the same type (i.e. 'play-pause')
      * to indicate they're equivalent.
      *
      * @param {string} type The type of element to track focus of.
-     * @param {string} query The selector of the element from this row's root.
+     * @param {string|HTMLElement} query The selector of the element from this

[hcarmona, 2017/03/16 21:31:54]

nit: rename |query| to |selector|

[scottchen, 2017/03/17 21:26:59]

good idea, wasn't sure what to name it.

+     *    row's root, or the element itself.
      * @return {boolean} Whether a new item was added.
      */
     addItem: function(type, query) {
       assert(type);
 
-      var element = this.root.querySelector(query);
+      var element;
+      if (query instanceof HTMLElement)
+        element = query;
+      else
+        element = this.root.querySelector(/** @type {string} */ (query));
       if (!element)
         return false;
 
       element.setAttribute('focus-type', type);
       element.tabIndex = this.isActive() ? 0 : -1;
 
       this.eventTracker.add(element, 'blur', this.onBlur_.bind(this));
       this.eventTracker.add(element, 'focus', this.onFocus_.bind(this));
       this.eventTracker.add(element, 'keydown', this.onKeydown_.bind(this));
       this.eventTracker.add(element, 'mousedown', this.onMousedown_.bind(this));
@@ skipping 159 matching lines @@
         this.getEquivalentElement(elementToFocus).focus();
         e.preventDefault();
       }
     },
   };
 
   return {
     FocusRow: FocusRow,
   };
 });