Install barback from a hosted source in all tests.

test/dart2js/output_can_be_consumed_by_successive_phases.dart

 // Copyright (c) 2013, 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.
 
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
 import '../serve/utils.dart';
 
 /// The code for a transformer that renames ".js" files to ".out".
 const JS_REWRITE_TRANSFORMER = """
@@ skipping 10 matching lines @@
     return transform.primaryInput.readAsString().then((contents) {
       var id = transform.primaryInput.id.changeExtension(".out");
       transform.addOutput(new Asset.fromString(id, contents));
     });
   }
 }
 """;
 
 main() {
   integration("output can be consumed by successive phases", () {
+    serveBarback();
+
     d.dir(appPath, [
       d.pubspec({
         "name": "myapp",
-        "transformers": ["\$dart2js", "myapp/src/transformer"]
+        "transformers": ["\$dart2js", "myapp/src/transformer"],
+        "dependencies": {"barback": "any"}
       }),
       d.dir("lib", [d.dir("src", [
         d.file("transformer.dart", JS_REWRITE_TRANSFORMER)
       ])]),
       d.dir("web", [d.file("main.dart", "void main() {}")])
     ]).create();
 
-    createLockFile('myapp', pkg: ['barback']);
-
     pubGet();
     pubServe();
     requestShouldSucceed("main.dart.out", isUnminifiedDart2JSOutput);
     endPubServe();
   });
 }