fixes #157, renaming local library identifiers if needed.

test/codegen/expect/DeltaBlue.js

Index: test/codegen/expect/DeltaBlue.js
diff --git a/test/codegen/expect/DeltaBlue.js b/test/codegen/expect/DeltaBlue.js
index b1d4d68599afb5b580c1717ed622f78f79a52a7b..f951b764ba5ed90f13fcfc283c020ae28a5c6e2f 100644
--- a/test/codegen/expect/DeltaBlue.js
+++ b/test/codegen/expect/DeltaBlue.js
@@ -1,5 +1,7 @@
-var DeltaBlue;
-(function(exports) {
+var DeltaBlue = dart.defineLibrary(DeltaBlue, {});
+var BenchmarkBase = dart.lazyImport(BenchmarkBase);
+var core = dart.lazyImport(core);
+(function(exports, BenchmarkBase, core) {
   'use strict';
   // Function main: () → dynamic
   function main() {
@@ -466,4 +468,4 @@ var DeltaBlue;
   exports.chainTest = chainTest;
   exports.projectionTest = projectionTest;
   exports.change = change;
-})(DeltaBlue || (DeltaBlue = {}));
+})(DeltaBlue, BenchmarkBase, core);