Move parser and token related libraries into their own subfolder.

pkg/compiler/lib/src/scanner/token_map.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.
-
-library dart2js.tokens.token_map;
-
-import 'token.dart' show
-    Token;
-
-/**
- * Key class used in [TokenMap] in which the hash code for a token is based
- * on the [charOffset].
- */
-class TokenKey {
-  final Token token;
-  TokenKey(this.token);
-  int get hashCode => token.charOffset;
-  operator==(other) => other is TokenKey && token == other.token;
-}
-
-/// Map of tokens and the first associated comment.
-/*
- * This implementation was chosen among several candidates for its space/time
- * efficiency by empirical tests of running dartdoc on dartdoc itself. Time
- * measurements for the use of [Compiler.commentMap]:
- *
- * 1) Using [TokenKey] as key (this class): ~80 msec
- * 2) Using [TokenKey] as key + storing a separate map in each script: ~120 msec
- * 3) Using [Token] as key in a [Map]: ~38000 msec
- * 4) Storing comments is new field in [Token]: ~20 msec
- *    (Abandoned due to the increased memory usage)
- * 5) Storing comments in an [Expando]: ~14000 msec
- * 6) Storing token/comments pairs in a linked list: ~5400 msec
- */
-class TokenMap {
-  Map<TokenKey,Token> comments = new Map<TokenKey,Token>();
-
-  Token operator[] (Token key) {
-    if (key == null) return null;
-    return comments[new TokenKey(key)];
-  }
-
-  void operator[]= (Token key, Token value) {
-    if (key == null) return;
-    comments[new TokenKey(key)] = value;
-  }
-}