.java

function countWatches(rootScope) {
  var watchers = 0;
  function visit(scope) {
    if (scope.$$watchers) {
      watchers += scope.$$watchers.length;
    }
    if (scope.$$childHead) {
      visit(scope.$$childHead);
    }
    if (scope.$$nextSibling) {
      visit(scope.$$nextSibling);
    }
  }
  visit(rootScope);
  return watchers;
};