- Parse the return type of JS during resolution to know what can be instantiated there.

sdk/lib/_internal/compiler/implementation/enqueue.dart

Index: sdk/lib/_internal/compiler/implementation/enqueue.dart
===================================================================
--- sdk/lib/_internal/compiler/implementation/enqueue.dart	(revision 15508)
+++ sdk/lib/_internal/compiler/implementation/enqueue.dart	(working copy)
@@ -392,6 +392,11 @@
     universe.isChecks.add(type);
   }
 
+  void registerJsCall(Send node, ResolverVisitor resolver) {
+    nativeEnqueuer.registerJsCall(node, this, resolver);
+  }
+  
+
   void forEach(f(WorkItem work)) {
     while (!queue.isEmpty) {
       f(queue.removeLast()); // TODO(kasperl): Why isn't this removeFirst?