Polymer('paper-button', {

      publish: {

        /**
         * The label of the button.
         *
         * @attribute label
         * @type string
         * @default ''
         */
        label: '',

        /**
         * If true, the button will be styled as a "raised" button.
         *
         * @attribute raisedButton
         * @type boolean
         * @default false
         */
        raisedButton: {value: false, reflect: true},

        /**
         * (optional) The URL of an image for an icon to use in the button.
         * Should not use `icon` property if you are using this property.
         *
         * @attribute iconSrc
         * @type string
         * @default ''
         */
         iconSrc: '',

         /**
          * (optional) Specifies the icon name or index in the set of icons
          * available in the icon set. If using this property, load the icon
          * set separately where the icon is used. Should not use `src`
          * if you are using this property.
          *
          * @attribute icon
          * @type string
          * @default ''
          */
         icon: ''

      },

      z: 1,

      attached: function() {
        if (this.textContent && !this.textContent.match(/\s+/)) {
          console.warn('Using textContent to label the button is deprecated. Use the "label" property instead');
          this.label = this.textContent;
        }
      },

      activeChanged: function() {
        this.super();

        if (this.active) {
          // FIXME: remove when paper-ripple can have a default 'down' state.
          if (!this.lastEvent) {
            var rect = this.getBoundingClientRect();
            this.lastEvent = {
              x: rect.left + rect.width / 2,
              y: rect.top + rect.height / 2
            }
          }
          this.$.ripple.downAction(this.lastEvent);
        } else {
          this.$.ripple.upAction();
        }
        this.adjustZ();
      },

      focusedChanged: function() {
        this.super();
        this.adjustZ();
      },

      disabledChanged: function() {
        this.super();
        this.adjustZ();
      },

      // waitForSpillCompleted: function(callback) {
      //   this.async(callback, null, (this.$.ink.spillCompleted ? 0 : this.duration));
      // },

      // resetInk: function() {
      //   this.active = false;
      //   this.$.ink.reset();
      // },

      insideButton: function(x, y) {
        var rect = this.getBoundingClientRect();
        return (rect.left <= x) && (x <= rect.right) && (rect.top <= y) && (y <= rect.bottom);
      },

      adjustZ: function() {
        if (this.focused) {
          this.classList.add('paper-shadow-animate-z-1-z-2');
        } else {
          this.classList.remove('paper-shadow-animate-z-1-z-2');

          if (this.active) {
            this.z = 2;
          } else if (this.disabled) {
            this.z = 0;
          } else {
            this.z = 1;
          }

        }
      },

      downAction: function(e) {
        this.super(e);
        this.lastEvent = e;
      },

      labelChanged: function() {
        this.setAttribute('aria-label', this.label);
      }

    });