code: function () {
  		var result = 0;
  		utils.forEach(
  			this.$.tabs.getControls(),
  			function (tab){
  				var w = tab.origWidth() ;
  				// must add margin and padding of inner button and outer tab-item
  				result += w + 18 ;
  			}
  		);
  		return result;
  	}
docs: compute tab width by adding width of tabs contained in tab bar.
  
  @private