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

pkg/polymer/test/event_handlers_test.dart

Index: pkg/polymer/test/event_handlers_test.dart
diff --git a/pkg/polymer/test/event_handlers_test.dart b/pkg/polymer/test/event_handlers_test.dart
index 867266a79900cbd07f442e88f7647cb18d267def..0cbcfa083161c545c7f28156447d2da6d145a04e 100644
--- a/pkg/polymer/test/event_handlers_test.dart
+++ b/pkg/polymer/test/event_handlers_test.dart
@@ -97,14 +97,7 @@ class MiniModel extends Observable {
   String toString() => "<mini-model $index>";
 }
 
-main() {
-  Logger.root..level = Level.FINE
-      ..onRecord.listen((m) => print('${m.loggerName} ${m.message}'));
-
-  initPolymer();
-}
-
-@initMethod init() {
+@initMethod main() {
   useHtmlConfiguration();
 
   setUp(() => Polymer.onReady);