Apply several phases only to entrypoint files (which currently are identified as

pkg/polymer/lib/deploy.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS 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.
 
 /**
  * Temporary deploy command used to create a version of the app that can be
- * compiled with dart2js and deployed. This library should go away once `pub
- * deploy` can be configured to run barback transformers.
+ * compiled with dart2js and deployed. Following pub layout conventions, this
+ * script will treat any HTML file under a package 'web/' and 'test/'
+ * directories as entry points.
  *
- * From an application package you can run this program by calling dart with a
- * 'package:' url to this file:
+ * From an application package you can run deploy by creating a small program
+ * as follows:
  *
- *    dart package:polymer/deploy.dart
+ *    import "package:polymer/deploy.dart" as deploy;
+ *    main() => deploy.main();
+ *
+ * This library should go away once `pub deploy` can be configured to run
+ * barback transformers.
  */
 library polymer.deploy;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
 import 'package:barback/barback.dart';
 import 'package:path/path.dart' as path;
 import 'package:polymer/src/transform.dart' show phases;
@@ skipping 223 matching lines @@
     print(e.message);
     _showUsage(parser);
     return null;
   }
 }
 
 _showUsage(parser) {
   print('Usage: dart package:polymer/deploy.dart [options]');
   print(parser.getUsage());
 }