Split scannerlib.dart into several libraries.

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 'scannerlib.dart' show
+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;
@@ skipping 20 matching lines @@
   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;
   }
 }