Test closed world model after deserialization.

pkg/compiler/lib/src/elements/common.dart

Index: pkg/compiler/lib/src/elements/common.dart
diff --git a/pkg/compiler/lib/src/elements/common.dart b/pkg/compiler/lib/src/elements/common.dart
index 6c2e843b599703b441c9bd139cc7935dfc83be6e..85fd159df1e0a2ff2dd3491c9d06cc57b1c6b1b8 100644
--- a/pkg/compiler/lib/src/elements/common.dart
+++ b/pkg/compiler/lib/src/elements/common.dart
@@ -9,6 +9,8 @@ library elements.common;
 import '../common/names.dart' show
     Names,
     Uris;
+import '../core_types.dart' show
+    CoreClasses;
 import '../dart_types.dart' show
     DartType,
     InterfaceType,
@@ -430,6 +432,12 @@ abstract class ClassElementCommon implements ClassElement {
   }
 
   @override
+  bool implementsFunction(CoreClasses coreClasses) {
+    return asInstanceOf(coreClasses.functionClass) != null ||
+        callType != null;
+  }
+
+  @override
   bool isSubclassOf(ClassElement cls) {
     // Use [declaration] for both [this] and [cls], because
     // declaration classes hold the superclass hierarchy.