Removed polymer & mirror from Observatory

runtime/observatory/web/main.dart

Index: runtime/observatory/web/main.dart
diff --git a/runtime/observatory/web/main.dart b/runtime/observatory/web/main.dart
index 36c03ab1165391d55ef8b4c35ad74444bf05ff01..4f63d25bbea960ec722dd58361f24ac32c3d40a8 100644
--- a/runtime/observatory/web/main.dart
+++ b/runtime/observatory/web/main.dart
@@ -4,27 +4,15 @@
 
 import 'dart:html';
 import 'package:logging/logging.dart';
-import 'package:polymer/polymer.dart';
 import 'package:observatory/elements.dart';
 
 main() async {
   Logger.root.level = Level.INFO;
   Logger.root.onRecord.listen((LogRecord rec) {
-      if (rec.level == Level.WARNING &&
-          rec.message.startsWith('Error evaluating expression') &&
-          (rec.message.contains("Can't assign to null: ") ||
-           rec.message.contains('Expression is not assignable: '))) {
-        // Suppress flaky polymer errors.
-        return;
-      }
       print('${rec.level.name}: ${rec.time}: ${rec.message}');
   });
   await initElements();
   Logger.root.info('Starting Observatory');
-  await initPolymer();
-  Logger.root.info('Polymer initialized');
-  await Polymer.onReady;
-  Logger.root.info('Polymer elements have been upgraded');
   document.body.children
       .insert(0, document.createElement('observatory-application'));
 }