Pull the 'keyword' property into Token.

pkg/analyzer/lib/dart/ast/token.dart

 // Copyright (c) 2014, 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.
 
 /**
  * Defines the tokens that are produced by the scanner, used by the parser, and
  * referenced from the [AST structure](ast.dart).
  */
 library analyzer.dart.ast.token;
 
@@ skipping 232 matching lines @@
    */
   bool get isSynthetic;
 
   /**
    * Return `true` if this token represents an operator that can be defined by
    * users.
    */
   bool get isUserDefinableOperator;
 
   /**
+   * Return the keyword, if a keyword token, or `null` otherwise.
+   */
+  Keyword get keyword;
+
+  /**
    * Return the number of characters in the node's source range.
    */
   int get length;
 
   /**
    * Return the lexeme that represents this token.
    */
   String get lexeme;
 
   /**
@@ skipping 466 matching lines @@
  */
 class _EndOfFileTokenType extends TokenType {
   /**
    * Initialize a newly created token.
    */
   const _EndOfFileTokenType() : super._('EOF', TokenClass.NO_CLASS, '');
 
   @override
   String toString() => '-eof-';
 }