merge fasta.Token into analyzer.Token

pkg/front_end/lib/src/fasta/scanner/error_token.dart

 // Copyright (c) 2017, 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 licenset hat can be found in the LICENSE file.
 
 library dart_scanner.error_token;
 
-import '../../scanner/token.dart' show TokenType;
+import '../../scanner/token.dart' show TokenType, TokenWithComment;
 
 import '../fasta_codes.dart'
     show
         FastaCode,
         codeAsciiControlCharacter,
         codeEncoding,
         codeExpectedHexDigit,
         codeMissingExponent,
         codeNonAsciiIdentifier,
         codeNonAsciiWhitespace,
@@ skipping 41 matching lines @@
 
     default:
       return new NonAsciiIdentifierToken(character, charOffset);
   }
 }
 
 /// Common superclass for all error tokens.
 ///
 /// It's considered an implementation error to access [lexeme] of an
 /// [ErrorToken].
-abstract class ErrorToken extends Token {
-  ErrorToken(int charOffset) : super(charOffset);
-
-  TokenType get type => TokenType.BAD_INPUT;
+abstract class ErrorToken extends TokenWithComment {
+  ErrorToken(int offset) : super(TokenType.BAD_INPUT, offset, null);
 
   /// This is a token that wraps around an error message. Return 1
   /// instead of the size of the length of the error message.
   @override
-  int get charCount => 1;
+  int get length => 1;
 
   String get lexeme => throw assertionMessage;
 
-  bool get isIdentifier => false;
-
   String get assertionMessage;
 
   FastaCode get errorCode;
 
   int get character => null;
 
   String get start => null;
 
   int get endOffset => null;
 
   BeginGroupToken get begin => null;
 
   @override
-  Token copyWithoutComments() {
+  Token copy() {
     throw 'unsupported operation';
   }
 }
 
 /// Represents an encoding error.
 class EncodingErrorToken extends ErrorToken {
   EncodingErrorToken(int charOffset) : super(charOffset);
 
   String toString() => "EncodingErrorToken()";
 
@@ skipping 113 matching lines @@
   UnmatchedToken(BeginGroupToken begin)
       : this.begin = begin,
         super(begin.charOffset);
 
   String toString() => "UnmatchedToken(${begin.lexeme})";
 
   String get assertionMessage => "'$begin' isn't closed.";
 
   FastaCode get errorCode => codeUnmatchedToken;
 }