refactor(dropdown): remove isolated scope

Closes #1818

Author: bekos

Diff for: src/dropdown/dropdown.js

@@ -41,48 +41,62 @@ angular.module('ui.bootstrap.dropdown', [])
   };
 }])
 
-.controller('DropdownController', ['$scope', '$attrs', 'dropdownConfig', 'dropdownService', '$animate', function($scope, $attrs, dropdownConfig, dropdownService, $animate) {
-  var self = this, openClass = dropdownConfig.openClass;
+.controller('DropdownController', ['$scope', '$attrs', '$parse', 'dropdownConfig', 'dropdownService', '$animate', function($scope, $attrs, $parse, dropdownConfig, dropdownService, $animate) {
+  var self = this,
+      scope = $scope.$new(), // create a child scope so we are not polluting original one
+      openClass = dropdownConfig.openClass,
+      getIsOpen,
+      setIsOpen = angular.noop,
+      toggleInvoker = $attrs.onToggle ? $parse($attrs.onToggle) : angular.noop;
 
   this.init = function( element ) {
     self.$element = element;
-    $scope.isOpen = angular.isDefined($attrs.isOpen) ? $scope.$parent.$eval($attrs.isOpen) : false;
+
+    if ( $attrs.isOpen ) {
+      getIsOpen = $parse($attrs.isOpen);
+      setIsOpen = getIsOpen.assign;
+
+      $scope.$watch(getIsOpen, function(value) {
+        scope.isOpen = !!value;
+      });
+    }
   };
 
   this.toggle = function( open ) {
-    return $scope.isOpen = arguments.length ? !!open : !$scope.isOpen;
+    return scope.isOpen = arguments.length ? !!open : !scope.isOpen;
   };
 
   // Allow other directives to watch status
   this.isOpen = function() {
-    return $scope.isOpen;
+    return scope.isOpen;
   };
 
-  $scope.$watch('isOpen', function( value ) {
+  scope.$watch('isOpen', function( value ) {
     $animate[value ? 'addClass' : 'removeClass'](self.$element, openClass);
 
     if ( value ) {
-      dropdownService.open( $scope );
+      dropdownService.open( scope );
     } else {
-      dropdownService.close( $scope );
+      dropdownService.close( scope );
     }
 
-    $scope.onToggle({ open: !!value });
+    setIsOpen($scope, value);
+    toggleInvoker($scope, { open: !!value });
   });
 
   $scope.$on('$locationChangeSuccess', function() {
-    $scope.isOpen = false;
+    scope.isOpen = false;
+  });
+
+  $scope.$on('$destroy', function() {
+    scope.$destroy();
   });
 }])
 
 .directive('dropdown', function() {
   return {
     restrict: 'CA',
     controller: 'DropdownController',
-    scope: {
-      isOpen: '=?',
-      onToggle: '&'
-    },
     link: function(scope, element, attrs, dropdownCtrl) {
       dropdownCtrl.init( element );
     }