Replace bootstrap logic with 'boot.js', use 'component/dart' mime-type and add

pkg/polymer/test/property_change_test.dart

Index: pkg/polymer/test/property_change_test.dart
diff --git a/pkg/polymer/test/property_change_test.dart b/pkg/polymer/test/property_change_test.dart
index fbbda2ecf1fdb6cdbb881de579e766a467dac4f5..621be399448c0e282f743912e26d907f7d973f54 100644
--- a/pkg/polymer/test/property_change_test.dart
+++ b/pkg/polymer/test/property_change_test.dart
@@ -46,11 +46,12 @@ class XTest extends XBase {
   }
 }
 
-main() => initPolymer().run(() {
+@initMethod
+main() {
   useHtmlConfiguration();
 
   setUp(() => Polymer.onReady);
 
   test('bar change detected', () => _bar.future);
   test('zonk change detected', () => _zonk.future);
-});
+}