Register created closure class with the world.

pkg/compiler/lib/src/js_model/js_strategy.dart

Index: pkg/compiler/lib/src/js_model/js_strategy.dart
diff --git a/pkg/compiler/lib/src/js_model/js_strategy.dart b/pkg/compiler/lib/src/js_model/js_strategy.dart
index 94215a63b5411dff60d47ba7fad2c12a71baa0f1..d43c778b541ae91d0357a941d62817fcf2216b35 100644
--- a/pkg/compiler/lib/src/js_model/js_strategy.dart
+++ b/pkg/compiler/lib/src/js_model/js_strategy.dart
@@ -10,7 +10,7 @@ import '../common/tasks.dart';
 import '../common_elements.dart';
 import '../compiler.dart';
 import '../constants/constant_system.dart';
-import '../elements/elements.dart' show ClassElement, TypedefElement;
+import '../elements/elements.dart' show TypedefElement;
 import '../elements/entities.dart';
 import '../elements/types.dart';
 import '../enqueue.dart';
@@ -384,7 +384,24 @@ class JsClosedWorld extends ClosedWorldBase with KernelClosedWorldMixin {
             classSets);
 
   @override
-  void registerClosureClass(ClassElement cls) {
-    throw new UnimplementedError('JsClosedWorld.registerClosureClass');
+  void registerClosureClass(ClassEntity cls, bool fromInstanceMember) {
+    // Tell the hierarchy that this is the super class. then we can use
+    // .getSupertypes(class)
+    ClassEntity superclass = fromInstanceMember
+        ? commonElements.boundClosureClass
+        : commonElements.closureClass;
+    ClassHierarchyNode parentNode = getClassHierarchyNode(superclass);
+    ClassHierarchyNode node = new ClassHierarchyNode(
+        parentNode, cls, getHierarchyDepth(superclass) + 1);
+    addClassHierarchyNode(cls, node);
+    for (InterfaceType type in getOrderedTypeSet(superclass).types) {
+      // TODO(efortuna): assert that the FunctionClass is in this ordered set.
+      // If not, we need to explicitly add node as a subtype of FunctionClass.
+      ClassSet subtypeSet = getClassSet(type.element);
+      subtypeSet.addSubtype(node);
+    }
+    addClassSet(cls, new ClassSet(node));
+    elementMap.addClosureClass(cls, new InterfaceType(superclass, const []));
+    node.isDirectlyInstantiated = true;
   }
 }