one space before opening brace in class

tools/dom/src/native_DOMImplementation.dart

 // Copyright (c) 2012, 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.
 
 part of html;
 
 class _Utils {
   static double dateTimeToDouble(DateTime dateTime) =>
       dateTime.millisecondsSinceEpoch.toDouble();
   static DateTime doubleToDateTime(double dateTime) {
@@ skipping 335 matching lines @@
   });
 }
 
 final _printClosure = window.console.log;
 final _pureIsolatePrintClosure = (s) {
   _sendToHelperIsolate([_PRINT, s], null);
 };
 
 final _forwardingPrintClosure = _Utils.forwardingPrint;
 
- class _Timer implements Timer{
+ class _Timer implements Timer {
   var _canceler;
 
   _Timer(int milliSeconds, void callback(Timer timer), bool repeating) {
 
     if (repeating) {
       int id = window._setInterval(() {
         callback(this);
       }, milliSeconds);
       _canceler = () => window._clearInterval(id);
     } else {
@@ skipping 53 matching lines @@
   _send(msg) {
     _sendToHelperIsolate(msg, _sendPort);
   }
 
   bool get isActive => _isActive;
 }
 
 get _pureIsolateTimerFactoryClosure =>
     ((int milliSeconds, void callback(Timer time), bool repeating) =>
         new _PureIsolateTimer(milliSeconds, callback, repeating));