Check for duplicate library names

lib/runtime/dart/_foreign_helper.js

Index: lib/runtime/dart/_foreign_helper.js
diff --git a/lib/runtime/dart/_foreign_helper.js b/lib/runtime/dart/_foreign_helper.js
index 36cb36e86f86a63c21b1ea60147e7ae421d0affc..bea05ed2c965e15ac4da5fe7292524a953aca954 100644
--- a/lib/runtime/dart/_foreign_helper.js
+++ b/lib/runtime/dart/_foreign_helper.js
@@ -1,6 +1,7 @@
-var _foreign_helper = dart.defineLibrary(_foreign_helper, {});
-var core = dart.import(core);
-(function(exports, core) {
+dart.library('dart/_foreign_helper', null, /* Imports */[
+  'dart/core'
+], /* Lazy imports */[
+], function(exports, core) {
   'use strict';
   function JS(typeDescription, codeTemplate, arg0, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10, arg11) {
     if (arg0 === void 0)
@@ -156,4 +157,4 @@ var core = dart.import(core);
   exports.JS_EFFECT = JS_EFFECT;
   exports.JS_CONST = JS_CONST;
   exports.JS_STRING_CONCAT = JS_STRING_CONCAT;
-})(_foreign_helper, core);
+});