Pass in "mode" to transformer plugins.

pkg/polymer/lib/transformer.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.
 
 /** Transfomer used for pub-serve and pub-deploy. */
 library polymer.transformer;
 
 import 'package:barback/barback.dart';
 import 'package:observe/transform.dart';
 import 'src/build/code_extractor.dart';
@@ skipping 12 matching lines @@
  *
  * At the end of these phases, this tranformer produces a single entrypoint HTML
  * file with a single Dart script that can later be compiled with dart2js.
  */
 class PolymerTransformerGroup implements TransformerGroup {
   final Iterable<Iterable> phases;
 
   PolymerTransformerGroup(TransformOptions options)
       : phases = _createDeployPhases(options);
 
-  PolymerTransformerGroup.asPlugin(Map args) : this(_parseArgs(args));
+  PolymerTransformerGroup.asPlugin(BarbackSettings settings)
+      : this(_parseSettings(settings));
 }
 
-
-TransformOptions _parseArgs(Map args) {
+TransformOptions _parseSettings(BarbackSettings settings) {
+  var args = settings.transformer;
   return new TransformOptions(
       entryPoints: _readEntrypoints(args['entry_points']),
       directlyIncludeJS: args['js'] != false, // default to true
       contentSecurityPolicy: args['csp'] == true); // default to false
 }
 
 _readEntrypoints(value) {
   if (value == null) return null;
   var entryPoints = [];
   bool error;
@@ skipping 14 matching lines @@
 
 List<List<Transformer>> _createDeployPhases(TransformOptions options) {
   return [
     [new InlineCodeExtractor(options)],
     [new ObservableTransformer()],
     [new ImportInliner(options)],
     [new ScriptCompactor(options)],
     [new PolyfillInjector(options)]
   ];
 }