Set fileUri when creating library builders.

pkg/front_end/lib/src/fasta/dill/dill_loader.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.
 
 library fasta.dill_loader;
 
 import 'dart:async' show
     Future;
 
 import 'dart:io' show
@@ skipping 16 matching lines @@
     DillLibraryBuilder;
 
 class DillLoader extends Loader<Library> {
   Uri input;
 
   Program program;
 
   DillLoader(TargetImplementation target)
       : super(target);
 
-  DillLibraryBuilder read(Uri uri) => super.read(uri);
+  DillLibraryBuilder read(Uri uri, [Uri fileUri]) => super.read(uri, fileUri);
 
   Future<Null> buildOutline(DillLibraryBuilder builder) async {
     if (program == null) {
       byteCount = await new File.fromUri(input).length();
       setProgram(await loadProgramFromBinary(input.toFilePath()));
     }
     builder.library.classes.forEach(builder.addClass);
     builder.library.procedures.forEach(builder.addMember);
     builder.library.fields.forEach(builder.addMember);
   }
 
   Future<Null> buildBody(DillLibraryBuilder builder, _) {
     return buildOutline(builder);
   }
 
   void setProgram(Program program) {
     assert(input != null);
     this.program = program;
     for (Library library in program.libraries) {
       read(library.importUri).library = library;
     }
   }
 }