Initialize TokenizerBase int fields for better dart2js codegen.

pkg/csslib/lib/src/tokenizer_base.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.
 // Generated by scripts/tokenizer_gen.py.
 
 part of csslib.parser;
 
 /** Tokenizer state to support look ahead for Less' nested selectors. */
 class TokenizerState {
   final int index;
@@ skipping 34 matching lines @@
   // places where an identifier is expected. This was breaking selectors like:
   //     :lang(fr)
   // The assumption that "fr" always means fraction (and similar issue with
   // other units) doesn't seem valid. We probably should defer this
   // analysis until we reach places in the parser where units are expected.
   // I'm not sure this is tokenizing as described in the specs:
   //     http://dev.w3.org/csswg/css-syntax/
   //     http://dev.w3.org/csswg/selectors4/
   bool inSelector = false;
 
-  int _index;
-  int _startIndex;
+  int _index = 0;
+  int _startIndex = 0;
 
   static const String _CDATA_START = '<![CDATA[';
   static const String _CDATA_END = ']]>';
 
   TokenizerBase(this._file, this._text, this._skipWhitespace,
       [this._index = 0]);
 
   Token next();
   int getIdentifierKind();
 
@@ skipping 361 matching lines @@
 
   Token finishDot() {
     if (TokenizerHelpers.isDigit(_peekChar())) {
       eatDigits();
       return finishNumberExtra(TokenKind.DOUBLE);
     } else {
       return _finishToken(TokenKind.DOT);
     }
   }
 }
-