Use dart.tearoff helper at tearoff sites

test/codegen/expect/functions.js

Index: test/codegen/expect/functions.js
diff --git a/test/codegen/expect/functions.js b/test/codegen/expect/functions.js
index d9a9b4e06edc82da7948bcadbef72e43f8e8bc5f..d04ca40ab657ee37dfa0cadca82216aba14aadba 100644
--- a/test/codegen/expect/functions.js
+++ b/test/codegen/expect/functions.js
@@ -6,6 +6,15 @@ var core = dart.import(core);
     return dart.setType([new Foo()], core.List$(Foo));
   }
   dart.fn(bootstrap, () => dart.functionType(core.List$(Foo), []));
+  let A2B$ = dart.generic(function(A, B) {
+    let A2B = dart.typedef('A2B', () => dart.functionType(B, [A]));
+    return A2B;
+  });
+  let A2B = A2B$();
+  function id(f) {
+    return f;
+  }
+  dart.fn(id, () => dart.functionType(A2B$(Foo, Foo), [A2B$(Foo, Foo)]));
   class Foo extends core.Object {}
   dart.setSignature(Foo, {});
   function main() {
@@ -14,6 +23,9 @@ var core = dart.import(core);
   dart.fn(main, dart.void, []);
   // Exports:
   exports.bootstrap = bootstrap;
+  exports.A2B$ = A2B$;
+  exports.A2B = A2B;
+  exports.id = id;
   exports.Foo = Foo;
   exports.main = main;
 })(functions, core);