Remove unused API.

dart/sdk/lib/_internal/compiler/implementation/scanner/keyword.dart

 // Copyright (c) 2011, 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 scanner;
 
 /**
  * A keyword in the Dart programming language.
  */
 class Keyword {
@@ skipping 85 matching lines @@
 
   String toString() => syntax;
 }
 
 /**
  * Abstract state in a state machine for scanning keywords.
  */
 abstract class KeywordState {
   KeywordState(this.keyword);
 
-  bool isLeaf();
   KeywordState next(int c);
   final Keyword keyword;
 
   static KeywordState _KEYWORD_STATE;
   static KeywordState get KEYWORD_STATE {
     if (_KEYWORD_STATE == null) {
       List<String> strings =
           new List<String>(Keyword.values.length);
       for (int i = 0; i < Keyword.values.length; i++) {
         strings[i] = Keyword.values[i].syntax;
@@ skipping 48 matching lines @@
 
 /**
  * A state with multiple outgoing transitions.
  */
 class ArrayKeywordState extends KeywordState {
   final List<KeywordState> table;
 
   ArrayKeywordState(List<KeywordState> this.table, String syntax)
     : super((syntax == null) ? null : Keyword.keywords[syntax]);
 
-  bool isLeaf() => false;
-
   KeywordState next(int c) => table[c - $a];
 
   String toString() {
     StringBuffer sb = new StringBuffer();
     sb.write("[");
     if (keyword != null) {
       sb.write("*");
       sb.write(keyword);
       sb.write(" ");
     }
     List<KeywordState> foo = table;
     for (int i = 0; i < foo.length; i++) {
       if (foo[i] != null) {
         sb.write("${new String.fromCharCodes([i + $a])}: ${foo[i]}; ");
       }
     }
     sb.write("]");
     return sb.toString();
   }
 }
 
 /**
  * A state that has no outgoing transitions.
  */
 class LeafKeywordState extends KeywordState {
   LeafKeywordState(String syntax) : super(Keyword.keywords[syntax]);
 
-  bool isLeaf() => true;
-
   KeywordState next(int c) => null;
 
   String toString() => keyword.syntax;
 }