Added support for exports and re-exports.

tests/compiler/dart2js/patch_test.dart

Index: tests/compiler/dart2js/patch_test.dart
diff --git a/tests/compiler/dart2js/patch_test.dart b/tests/compiler/dart2js/patch_test.dart
index b0bc1096a44fae19eb1e6ee3e97d06be4bdad5ad..1e294c13f852b875725ca0c3ee114d78b2e19d23 100644
--- a/tests/compiler/dart2js/patch_test.dart
+++ b/tests/compiler/dart2js/patch_test.dart
@@ -15,7 +15,9 @@ Compiler applyPatch(String script, String patch) {
   MockCompiler compiler = new MockCompiler(coreSource: core);
   var uri = new Uri("core.dartp");
   compiler.sourceFiles[uri.toString()] = new MockFile(patch);
-  compiler.patchParser.patchLibrary(uri, compiler.coreLibrary);
+  var handler = new LibraryDependencyHandler(compiler);
+  compiler.patchParser.patchLibrary(handler, uri, compiler.coreLibrary);
+  handler.computeExports();
   return compiler;
 }