fix(compiler): change compiler to support attribute mapping for template decorators

Closes #1581

Author: vsavkin

lib/core_dom/view_factory.dart

@@ -232,12 +232,18 @@ class ViewFactoryCache {
 class _AnchorAttrs extends NodeAttrs {
   DirectiveRef _directiveRef;
 
-  _AnchorAttrs(DirectiveRef this._directiveRef): super(null);
+  _AnchorAttrs(DirectiveRef directiveRef)
+      : super(directiveRef.element),
+      _directiveRef = directiveRef;
 
-  String operator [](name) => name == '.' ? _directiveRef.value : null;
+  String operator [](name) => name == '.' ? _directiveRef.value : super[name];
 
   void observe(String attributeName, _AttributeChanged notifyFn) {
-    notifyFn(attributeName == '.' ? _directiveRef.value : null);
+    if (attributeName == '.') {
+      notifyFn(_directiveRef.value);
+    } else {
+      super.observe(attributeName, notifyFn);
+    }
   }
 }
 

test/core_dom/compiler_spec.dart

@@ -56,7 +56,8 @@ void main() {
           ..bind(Parent, toValue: null)
           ..bind(Child)
           ..bind(ChildTemplateComponent)
-          ..bind(InjectorDependentComponent);
+          ..bind(InjectorDependentComponent)
+          ..bind(TranscludeChildrenWithAttributeDirective);
     });
 
     beforeEach((TestBed tb) => _ = tb);
@@ -1149,6 +1150,14 @@ void main() {
         expect(logger).toContain('LazyPane-0');
       }));
     });
+
+    it('should set attributes on a directive transcluding its children', () {
+      _.compile('<div><transclude-children-with-attr attr="value"/></div>');
+      _.rootScope.apply();
+
+      var dir = _.rootScope.context['transclude-children-with-attr'];
+      expect(dir.attr).toEqual('value');
+    });
   }));
 }
 
@@ -1234,6 +1243,20 @@ class SimpleTranscludeInAttachAttrDirective {
   }
 }
 
+@Decorator(
+    children: Directive.TRANSCLUDE_CHILDREN,
+    selector:'transclude-children-with-attr',
+    map: const {
+        'attr': '@attr'
+    })
+class TranscludeChildrenWithAttributeDirective {
+  var attr;
+
+  TranscludeChildrenWithAttributeDirective(RootScope scope) {
+    scope.context['transclude-children-with-attr'] = this;
+  }
+}
+
 @Decorator(selector: '[include-transclude]')
 class IncludeTranscludeAttrDirective {
   IncludeTranscludeAttrDirective(SimpleTranscludeInAttachAttrDirective simple, Logger log) {