Drop support for older Barback versions.

test/transformer/can_use_has_input_test.dart

 // 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.
 
 library pub_tests;
 
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
 import '../serve/utils.dart';
 
@@ skipping 15 matching lines @@
       var id = transform.primaryInput.id.changeExtension(".out");
       var asset = new Asset.fromString(id,
           "primary: \${results[0]}, secondary: \${results[1]}");
       transform.addOutput(asset);
     });
   }
 }
 """;
 
 main() {
-  withBarbackVersions("any", () {
-    integration("a transform can use hasInput", () {
-      d.dir(appPath, [
-        d.pubspec({
-          "name": "myapp",
-          "transformers": ["myapp/src/transformer"]
-        }),
-        d.dir("lib", [d.dir("src", [
-          d.file("transformer.dart", TRANSFORMER)
-        ])]),
-        d.dir("web", [
-          d.file("foo.txt", "foo")
-        ])
-      ]).create();
+   integration("a transform can use hasInput", () {
+     d.dir(appPath, [
+       d.pubspec({
+         "name": "myapp",
+         "transformers": ["myapp/src/transformer"]
+       }),
+       d.dir("lib", [d.dir("src", [
+         d.file("transformer.dart", TRANSFORMER)
+       ])]),
+       d.dir("web", [
+         d.file("foo.txt", "foo")
+       ])
+     ]).create();
 
-      createLockFile('myapp', pkg: ['barback']);
+     createLockFile('myapp', pkg: ['barback']);
 
-      pubServe();
-      requestShouldSucceed("foo.out", "primary: true, secondary: false");
-      endPubServe();
-    });
-  });
+     pubServe();
+     requestShouldSucceed("foo.out", "primary: true, secondary: false");
+     endPubServe();
+   });
 }