feat(forms): provide support for parent form communication

lib/directive/ng_form.dart

@@ -8,13 +8,17 @@ part of angular.directive;
 @NgDirective(
     selector: 'form',
     visibility: NgDirective.CHILDREN_VISIBILITY)
+@NgDirective(
+    selector: 'fieldset',
+    visibility: NgDirective.CHILDREN_VISIBILITY)
 @NgDirective(
     selector: '.ng-form',
     visibility: NgDirective.CHILDREN_VISIBILITY)
 @NgDirective(
     selector: '[ng-form]',
     visibility: NgDirective.CHILDREN_VISIBILITY)
 class NgForm extends NgControl implements NgDetachAware {
+  final NgForm _parentForm;
   final dom.Element _element;
   final Scope _scope;
 
@@ -23,7 +27,9 @@ class NgForm extends NgControl implements NgDetachAware {
   final List<NgControl> _controls = new List<NgControl>();
   final Map<String, NgControl> _controlByName = new Map<String, NgControl>();
 
-  NgForm(this._scope, this._element) {
+  NgForm(this._scope, dom.Element this._element, Injector injector):
+    _parentForm = injector.parent.get(NgForm)
+  {
     if(!this._element.attributes.containsKey('action')) {
       this._element.onSubmit.listen((event) {
         event.preventDefault();
@@ -59,12 +65,14 @@ class NgForm extends NgControl implements NgDetachAware {
           if(currentErrors.isEmpty) {
             valid = true;
           }
+          _parentForm.setValidity(this, errorType, true);
         }
       }
     } else {
       if(queue == null) {
         queue = new List<NgControl>();
         currentErrors[errorType] = queue;
+        _parentForm.setValidity(this, errorType, false);
       } else if(queue.contains(control)) {
         return;
       }

test/directive/ng_form_spec.dart

@@ -163,6 +163,43 @@ describe('form', () {
       expect(form.valid).toBe(true);
       expect(form.invalid).toBe(false);
     }));
+
+    it('should set the validity for the parent form when fieldsets are used', inject((Scope scope) {
+      var element = $('<form name="myForm">' + 
+                      '  <fieldset probe="f">' +
+                      '    <input type="text" ng-model="one" name="one" probe="m" />' +
+                      '  </fieldset>' +
+                      '</form>');
+
+      _.compile(element);
+      scope.$apply();
+
+      var form = scope['myForm'];
+      var fieldset = _.rootScope.f.directive(NgForm);
+      var model = _.rootScope.m.directive(NgModel);
+
+      model.setValidity("error", false);
+
+      expect(model.valid).toBe(false);
+      expect(fieldset.valid).toBe(false);
+      expect(form.valid).toBe(false);
+
+      model.setValidity("error", true);
+
+      expect(model.valid).toBe(true);
+      expect(fieldset.valid).toBe(true);
+      expect(form.valid).toBe(true);
+
+      form.setValidity(fieldset, "error", false);
+      expect(model.valid).toBe(true);
+      expect(fieldset.valid).toBe(true);
+      expect(form.valid).toBe(false);
+
+      fieldset.setValidity(model, "error", false);
+      expect(model.valid).toBe(true);
+      expect(fieldset.valid).toBe(false);
+      expect(form.valid).toBe(false);
+    }));
   });
 
   describe('controls', () {