MD Settings: Update passwords section for new cr-shared-menu features

ui/webui/resources/cr_elements/cr_shared_menu/cr_shared_menu.js

 // Copyright 2016 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.
 
 /** Same as paper-menu-button's custom easing cubic-bezier param. */
 var SLIDE_CUBIC_BEZIER = 'cubic-bezier(0.3, 0.95, 0.5, 1)';
 
 Polymer({
   is: 'cr-shared-menu',
 
@@ skipping 95 matching lines @@
 
   /**
    * The last focusable child in the menu's light DOM.
    * @private {?Element}
    */
   lastFocus_: null,
 
   /** @override */
   attached: function() {
     window.addEventListener('resize', this.closeMenu.bind(this));
-
-    var focusableChildren = Polymer.dom(this).querySelectorAll(
-        '[tabindex],button');
-    if (focusableChildren.length > 0) {
-      this.$.dropdown.focusTarget = focusableChildren[0];
-      this.firstFocus_ = focusableChildren[0];
-      this.lastFocus_ = focusableChildren[focusableChildren.length - 1];
-    }
   },
 
   /** Closes the menu. */
   closeMenu: function() {
     if (this.root.activeElement == null) {
       // Something else has taken focus away from the menu. Do not attempt to
       // restore focus to the button which opened the menu.
       this.$.dropdown.restoreFocusOnClose = false;
     }
     this.menuOpen = false;
     this.$.dropdown.restoreFocusOnClose = true;
   },
 
   /**
    * Opens the menu at the anchor location.
    * @param {!Element} anchor The location to display the menu.
    * @param {!Object} itemData The contextual item's data.
    */
   openMenu: function(anchor, itemData) {
     this.itemData = itemData;
     this.lastAnchor_ = anchor;
 
+    var focusableChildren = Polymer.dom(this).querySelectorAll(
+        '[tabindex]:not([hidden]),button:not([hidden])');

[Dan Beam, 2016/07/14 17:09:20]

and it starts growing

[tsergeant, 2016/07/15 01:17:48]

https://www.youtube.com/watch?v=bWcASV2sey0

https://github.com/PolymerElements/iron-overlay-behavior/pull/200

+    if (focusableChildren.length > 0) {
+      this.$.dropdown.focusTarget = focusableChildren[0];
+      this.firstFocus_ = focusableChildren[0];
+      this.lastFocus_ = focusableChildren[focusableChildren.length - 1];
+    }
+
     // Move the menu to the anchor.
     this.$.dropdown.positionTarget = anchor;
     this.menuOpen = true;
   },
 
   /**
    * Toggles the menu for the anchor that is passed in.
    * @param {!Element} anchor The location to display the menu.
    * @param {!Object} itemData The contextual item's data.
    */
@@ skipping 32 matching lines @@
   /**
    * Ensure the menu is reset properly when it is closed by the dropdown (eg,
    * clicking outside).
    * @private
    */
   menuOpenChanged_: function() {
     if (!this.menuOpen)
       this.itemData = null;
   },
 });