Only pass an AssetId to isPrimary and declareOutputs.

samples/third_party/dromaeo/lib/transformer.dart

Index: samples/third_party/dromaeo/lib/transformer.dart
diff --git a/samples/third_party/dromaeo/lib/transformer.dart b/samples/third_party/dromaeo/lib/transformer.dart
index 88fb58485fdd0040d3ed427a19fe0bde0c0fffeb..fa50ea3d87b07162273774f261fab355e8e5c1a9 100644
--- a/samples/third_party/dromaeo/lib/transformer.dart
+++ b/samples/third_party/dromaeo/lib/transformer.dart
@@ -13,9 +13,9 @@ class DromaeoTransformer extends Transformer {
 
   /// The index.html file and the tests/dom-*-html.html files are the ones we
   /// apply this transform to.
-  Future<bool> isPrimary(Asset asset) {
+  Future<bool> isPrimary(AssetId id) {
     var reg = new RegExp('(tests/dom-.+-html\.html\$)|(index\.html\$)');
-    return new Future.value(reg.hasMatch(asset.id.path));
+    return new Future.value(reg.hasMatch(id.path));
   }
 
   Future apply(Transform transform) {