Function updateLabelMap

test/angular/1.3/angular.js:26095–26098

* A new labelMap is created with each render. * This function is called for each existing option with added=false, * and each new option with added=true. * - Labels that are passed to this method twice, * (once with added=true and once with added=false) will end u

(labelMap, label, added)

         * value of 1 and will eventually be passed to selectCtrl.addOption()
        */
        function updateLabelMap(labelMap, label, added) {
          labelMap[label] = labelMap[label] || 0;
          labelMap[label] += (added ? 1 : -1);
        }

        function render() {
          renderScheduled = false;