Load time improvements (fixes #140)

lib/runtime/messages_widget.dart

 // Copyright (c) 2015, 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.
 
 /// This library provides a single function called injectLogs which when called
 /// will request a logs json file and build a small widget out of them which
 /// groups the logs by level.
 library polymer.build.log_injector;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:html';
 
 import 'package:path/path.dart' as path;
 import 'package:source_span/source_span.dart';
 import 'package:dev_compiler/src/summary.dart';
 
-main() async => displayMessages(await HttpRequest.getString('messages.json'));
+main() async {
+  await window.animationFrame;
+  displayMessages(await HttpRequest.getString('messages.json'));
+}
 
 void displayMessages(String data) {
   var summary = GlobalSummary.parse(JSON.decode(data));
   var messagesByLevel = _getMessagesByLevel(summary);
   if (messagesByLevel.isEmpty) return;
 
   // Build the wrapper, menu, and content divs.
   var menuWrapper = new DivElement()..classes.add('menu');
   var contentWrapper = new DivElement()..classes.add('content');
   var wrapperDiv = new DivElement()
@@ skipping 94 matching lines @@
 class _Visitor extends RecursiveSummaryVisitor {
   final Map<String, List<MessageSummary>> messagesByLevel = {};
 
   @override
   void visitMessage(MessageSummary message) {
     var level = message.level.toLowerCase();
     messagesByLevel.putIfAbsent(level, () => []);
     messagesByLevel[level].add(message);
   }
 }