Emit declarations for typedefs that are needed by reflection.

tests/lib/mirrors/relation_subclass_test.dart

 // Copyright (c) 2014, 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 test.relation_subclass;
 
 import "dart:mirrors";
 
 import "package:expect/expect.dart";
 
@@ skipping 39 matching lines @@
   Expect.isFalse(Obj.isSubclassOf(Sub2));
 
   Expect.isTrue(Super.isSubclassOf(Obj));
   Expect.isFalse(Obj.isSubclassOf(Super));
 
   var Func = coreLibrary.declarations[#Function];
   Expect.isTrue(Func.isSubclassOf(Obj));
   Expect.isFalse(Obj.isSubclassOf(Func));
 
   // Function typedef.
-  // TODO(16939): retrieve via declaration when dart2js supports it.
-  var NumPred = reflectType(NumberPredicate);
-  var IntPred = reflectType(IntegerPredicate);
-  var DubPred = reflectType(DoublePredicate);
-  var NumGen = reflectType(NumberGenerator);
-  var IntGen = reflectType(IntegerGenerator);
-  var DubGen = reflectType(DoubleGenerator);
+  var NumPred = thisLibrary.declarations[#NumberPredicate];
+  var IntPred = thisLibrary.declarations[#IntegerPredicate];
+  var DubPred = thisLibrary.declarations[#DoublePredicate];
+  var NumGen = thisLibrary.declarations[#NumberGenerator];
+  var IntGen = thisLibrary.declarations[#IntegerGenerator];
+  var DubGen = thisLibrary.declarations[#DoubleGenerator];
 
   isArgumentOrTypeError(e) => e is ArgumentError || e is TypeError;
   Expect.throws(() => Func.isSubclassOf(NumPred), isArgumentOrTypeError);
   Expect.throws(() => Func.isSubclassOf(IntPred), isArgumentOrTypeError);
   Expect.throws(() => Func.isSubclassOf(DubPred), isArgumentOrTypeError);
   Expect.throws(() => Func.isSubclassOf(NumGen), isArgumentOrTypeError);
   Expect.throws(() => Func.isSubclassOf(IntGen), isArgumentOrTypeError);
   Expect.throws(() => Func.isSubclassOf(DubGen), isArgumentOrTypeError);
 
   isNoSuchMethodError(e) => e is NoSuchMethodError;
@@ skipping 25 matching lines @@
   // IntPredRef.isSubclassOf(Func);
   // DubPredRef.isSubclassOf(Func);
   // NumGenRef.isSubclassOf(Func);
   // IntGenRef.isSubclassOf(Func);
   // DubGenRef.isSubclassOf(Func);
 }
 
 main() {
   test(currentMirrorSystem());
 }