update fasta scanner to generate two types of comments

pkg/front_end/lib/src/fasta/scanner/array_based_scanner.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.
 
 library fasta.scanner.array_based_scanner;
 
 import 'error_token.dart' show ErrorToken;
 
 import 'keyword.dart' show Keyword;
 
-import 'precedence.dart' show COMMENT_INFO, EOF_INFO, PrecedenceInfo;
+import 'precedence.dart' show EOF_INFO, PrecedenceInfo;
 
 import 'token.dart'
     show BeginGroupToken, KeywordToken, StringToken, SymbolToken, Token;
 
 import 'token_constants.dart'
     show
         LT_TOKEN,
         OPEN_CURLY_BRACKET_TOKEN,
         OPEN_PAREN_TOKEN,
         STRING_INTERPOLATION_TOKEN;
@@ skipping 196 matching lines @@
       // '<', the inner '<' is left without endGroup.
       groupingStack = groupingStack.tail;
     }
     if (groupingStack.isEmpty) return;
     if (identical(groupingStack.head.kind, LT_TOKEN)) {
       groupingStack.head.endGroup = tail;
       groupingStack = groupingStack.tail;
     }
   }
 
-  void appendComment(start, bool asciiOnly) {
+  void appendComment(start, PrecedenceInfo info, bool asciiOnly) {
     if (!includeComments) return;
-    Token newComment = createSubstringToken(COMMENT_INFO, start, asciiOnly);
+    Token newComment = createSubstringToken(info, start, asciiOnly);
     if (comments == null) {
       comments = newComment;
       commentsTail = comments;
     } else {
       commentsTail.next = newComment;
       commentsTail.next.previousToken = commentsTail;
       commentsTail = commentsTail.next;
     }
   }
 
@@ skipping 31 matching lines @@
    * something which cannot possibly be part of a type parameter/argument
    * list, like the '=' in the above example.
    */
   void discardOpenLt() {
     while (!groupingStack.isEmpty &&
         identical(groupingStack.head.kind, LT_TOKEN)) {
       groupingStack = groupingStack.tail;
     }
   }
 }