Parse script tags with Fasta.

pkg/front_end/lib/src/fasta/scanner/abstract_scanner.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 fasta.scanner.abstract_scanner;
 
 import 'dart:collection' show ListMixin;
 
 import 'dart:typed_data' show Uint16List, Uint32List;
 
@@ skipping 385 matching lines @@
 
     next = currentAsUnicode(next);
 
     return unexpected(next);
   }
 
   int tokenizeTag(int next) {
     // # or #!.*[\n\r]
     if (scanOffset == 0) {
       if (identical(peek(), $BANG)) {
-        int start = scanOffset + 1;
+        int start = scanOffset;
         bool asciiOnly = true;
         do {
           next = advance();
           if (next > 127) asciiOnly = false;
         } while (!identical(next, $LF) &&
             !identical(next, $CR) &&
             !identical(next, $EOF));
         if (!asciiOnly) handleUnicode(start);
+        appendSubstringToken(SCRIPT_INFO, start, asciiOnly);
         return next;
       }
     }
     appendPrecedenceToken(HASH_INFO);
     return advance();
   }
 
   int tokenizeTilde(int next) {
     // ~ ~/ ~/=
     next = advance();
@@ skipping 819 matching lines @@
       switchToUint32(newLength);
     }
   }
 
   void switchToUint32(int newLength) {
     final newArray = new Uint32List(newLength);
     newArray.setRange(0, arrayLength, array);
     array = newArray;
   }
 }