Fix type masks for js-interop types.

pkg/compiler/lib/src/resolution/class_members.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library dart2js.resolution.compute_members;
 
 import '../common.dart';
 import '../common/names.dart' show Identifiers, Names;
 import '../common/resolution.dart' show Resolution;
 import '../dart_types.dart';
@@ skipping 51 matching lines @@
   void computeMembersByName(String name, Setlet<Name> names) {
     computeMembers(name, names);
   }
 
   /// Compute all members of [cls] and checked that [cls] implements its
   /// interface unless it is abstract or declares a `noSuchMethod` method.
   void computeAllMembers() {
     computeMembers(null, null);
     if (!cls.isAbstract) {
       Member member = classMembers[Names.noSuchMethod_];
-      if (member != null && !member.declarer.isObject) {
+      if (member != null &&
+          !resolution.target.isDefaultNoSuchMethod(member.element)) {
         return;
       }
       // Check for unimplemented members on concrete classes that neither have
       // a `@proxy` annotation nor declare a `noSuchMethod` method.
       checkInterfaceImplementation();
     }
   }
 
   /// Compute declared and inherited members of [cls] and return a map of the
   /// declared members.
@@ skipping 872 matching lines @@
         message: "Members have not been fully computed for $this."));
     if (interfaceMembersAreClassMembers) {
       classMembers.forEach((_, member) {
         if (!member.isStatic) f(member);
       });
     } else {
       interfaceMembers.forEach((_, member) => f(member));
     }
   }
 }