[Polymer] Roll polymer to latest version

third_party/polymer/v1_0/components-chromium/paper-dropdown-menu/paper-dropdown-menu-extracted.js

 (function() {
       'use strict';
 
       Polymer({
         is: 'paper-dropdown-menu',
 
         /**
          * Fired when the dropdown opens.
          *
          * @event paper-dropdown-open
@@ skipping 228 matching lines @@
           // NOTE(cdata): These numbers are somewhat magical because they are
           // derived from the metrics of elements internal to `paper-input`'s
           // template. The metrics will change depending on whether or not the
           // input has a floating label.
           return noLabelFloat ? -4 : 8;
         },
 
         /**
          * Returns false if the element is required and does not have a selection,
          * and true otherwise.
+         * @param {*=} _value Ignored.
          * @return {boolean} true if `required` is false, or if `required` is true
          * and the element has a valid selection.
          */
-        _getValidity: function() {
-          return this.disabled || !this.required || (this.required && this.value);
+        _getValidity: function(_value) {
+          return this.disabled || !this.required || (this.required && !!this.value);
         },
 
         _openedChanged: function() {
           var openState = this.opened ? 'true' : 'false';
           var e = this.contentElement;
           if (e) {
             e.setAttribute('aria-expanded', openState);
           }
         }
       });
     })();