[Fasta] include source code in dill

pkg/kernel/lib/ast.dart

 // Copyright (c) 2016, 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.
 
 /// -----------------------------------------------------------------------
 ///                           ERROR HANDLING
 /// -----------------------------------------------------------------------
 ///
 /// As a rule of thumb, errors that can be detected statically are handled by
 /// the frontend, typically by translating the erroneous code into a 'throw' or
@@ skipping 4001 matching lines @@
     if (node == child) {
       return replacement;
     } else {
       return node;
     }
   }
 }
 
 class Source {
   final List<int> lineStarts;
-  final String source;
+  final List<int> source;
 
   Source(this.lineStarts, this.source);
 }
 
 /// Returns the [Reference] object for the given member.
 ///
 /// Returns `null` if the member is `null`.
 Reference getMemberReference(Member member) {
   return member?.reference;
 }
@@ skipping 33 matching lines @@
 /// library has not been assigned a canonical name yet.
 ///
 /// Returns `null` if the library is `null`.
 CanonicalName getCanonicalNameOfLibrary(Library library) {
   if (library == null) return null;
   if (library.canonicalName == null) {
     throw '$library has no canonical name';
   }
   return library.canonicalName;
 }