Check for duplicate library names

test/codegen/expect/methods.js

Index: test/codegen/expect/methods.js
diff --git a/test/codegen/expect/methods.js b/test/codegen/expect/methods.js
index 211a874d9bd9de4562fa9f9e6e777826c05926f6..ead2fa003f95a05d7e51433a94a0b1784965cac3 100644
--- a/test/codegen/expect/methods.js
+++ b/test/codegen/expect/methods.js
@@ -1,6 +1,7 @@
-var methods = dart.defineLibrary(methods, {});
-var core = dart.import(core);
-(function(exports, core) {
+dart.library('methods.js', null, /* Imports */[
+  'dart/core.js'
+], /* Lazy imports */[
+], function(exports, core) {
   'use strict';
   let _c = Symbol('_c');
   class A extends core.Object {
@@ -79,4 +80,4 @@ var core = dart.import(core);
   exports.Bar = Bar;
   exports.Foo = Foo;
   exports.test = test;
-})(methods, core);
+});