feat(NgForm): provide access to non-uniquely named control instances via form.controls

Closes #642

Author: matsko

lib/directive/ng_form.dart

@@ -57,14 +57,18 @@ class NgForm extends NgControl {
     }
   }
 
+  get controls => _controlByName;
+
   NgControl operator[](name) {
-    if (_controlByName.containsKey(name)) {
-      return _controlByName[name][0];
+    if (controls.containsKey(name)) {
+      return controls[name][0];
     }
   }
 }
 
 class NgNullForm extends NgNullControl implements NgForm {
   NgNullForm() {}
   operator[](name) {}
+
+  get controls => null;
 }

test/directive/ng_form_spec.dart

@@ -40,6 +40,30 @@ void main() {
       expect(scope.eval("myForm['model']")).toBe(one);
     }));
 
+    it('should return the all the controls with the given name', inject((Scope scope, TestBed _) {
+      var element = $('<form name="myForm">' +
+                      '  <input type="text" name="model" ng-model="modelOne" probe="a" />' +
+                      '  <input type="text" name="model" ng-model="modelTwo" probe="b" />' +
+                      '</form>');
+
+      _.compile(element);
+      scope.apply();
+
+      NgForm form = _.rootScope.context['myForm'];
+      NgModel one = _.rootScope.context['a'].directive(NgModel);
+      NgModel two = _.rootScope.context['b'].directive(NgModel);
+
+      expect(one).not.toBe(two);
+
+      var controls = form.controls['model'];
+      expect(controls[0]).toBe(one);
+      expect(controls[1]).toBe(two);
+
+      expect(scope.eval("myForm.controls['model'][0]")).toBe(one);
+      expect(scope.eval("myForm.controls['model'][1]")).toBe(two);
+    }));
+
+
     describe('pristine / dirty', () {
       it('should be set to pristine by default', inject((Scope scope, TestBed _) {
         var element = $('<form name="myForm"></form>');