Support loading transformers exported by packages' libraries.

sdk/lib/_internal/pub/test/transformer/loads_a_transformer_defined_in_an_exported_library_test.dart

Index: sdk/lib/_internal/pub/test/transformer/loads_a_transformer_defined_in_an_exported_library_test.dart
diff --git a/sdk/lib/_internal/pub/test/transformer/runs_a_local_transform_on_the_application_package_test.dart b/sdk/lib/_internal/pub/test/transformer/loads_a_transformer_defined_in_an_exported_library_test.dart
similarity index 62%
copy from sdk/lib/_internal/pub/test/transformer/runs_a_local_transform_on_the_application_package_test.dart
copy to sdk/lib/_internal/pub/test/transformer/loads_a_transformer_defined_in_an_exported_library_test.dart
index a9e3e8f1beb822d476477c885ea3981a4f3b4679..d38baa6bea1f333ed8a54cb2c5457b0db20609ec 100644
--- a/sdk/lib/_internal/pub/test/transformer/runs_a_local_transform_on_the_application_package_test.dart
+++ b/sdk/lib/_internal/pub/test/transformer/loads_a_transformer_defined_in_an_exported_library_test.dart
@@ -1,4 +1,4 @@
-// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS d.file
+// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS d.file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
@@ -10,15 +10,18 @@ import '../serve/utils.dart';
 
 main() {
   initConfig();
-  integration("runs a local transform on the application package", () {
+  integration("loads a transformer defined in an exported library", () {
     d.dir(appPath, [
       d.pubspec({
         "name": "myapp",
-        "transformers": ["myapp/src/transformer"]
+        "transformers": ["myapp"]
       }),
-      d.dir("lib", [d.dir("src", [
-        d.file("transformer.dart", REWRITE_TRANSFORMER)
-      ])]),
+      d.dir("lib", [
+        d.file("myapp.dart", "export 'src/transformer.dart';"),
+        d.dir("src", [
+          d.file("transformer.dart", REWRITE_TRANSFORMER)
+        ])
+      ]),
       d.dir("web", [
         d.file("foo.txt", "foo")
       ])