Function beginPhase

lib/test/angular/1.8.0/angular.js:19824–19830

(phase)

    function beginPhase(phase) {
      if ($rootScope.$$phase) {
        throw $rootScopeMinErr('inprog', '{0} already in progress', $rootScope.$$phase);
      }

      $rootScope.$$phase = phase;
    }

    function clearPhase() {
      $rootScope.$$phase = null;