Pass a Target instance to DillTarget instead of its name

pkg/front_end/lib/src/incremental_kernel_generator_impl.dart

 // Copyright (c) 2017, 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.
 
 import 'dart:async';
 import 'dart:io';
 
 import 'package:front_end/file_system.dart';
 import 'package:front_end/incremental_kernel_generator.dart';
 import 'package:front_end/src/base/api_signature.dart';
 import 'package:front_end/src/base/performace_logger.dart';
 import 'package:front_end/src/base/processed_options.dart';
 import 'package:front_end/src/fasta/dill/dill_library_builder.dart';
 import 'package:front_end/src/fasta/dill/dill_target.dart';
 import 'package:front_end/src/fasta/kernel/kernel_target.dart';
 import 'package:front_end/src/fasta/ticker.dart';
 import 'package:front_end/src/fasta/translate_uri.dart';
 import 'package:front_end/src/incremental/byte_store.dart';
 import 'package:front_end/src/incremental/file_state.dart';
 import 'package:kernel/binary/ast_from_binary.dart';
 import 'package:kernel/binary/limited_ast_to_binary.dart';
 import 'package:kernel/kernel.dart' hide Source;
 import 'package:kernel/target/targets.dart' show TargetFlags;
+import 'package:kernel/target/vm_fasta.dart' show VmFastaTarget;
 
 dynamic unimplemented() {
   // TODO(paulberry): get rid of this.
   throw new UnimplementedError();
 }
 
 class ByteSink implements Sink<List<int>> {
   final BytesBuilder builder = new BytesBuilder();
 
   void add(List<int> data) {
@@ skipping 61 matching lines @@
       FileState entryLibrary = await _fsState.getFile(_entryPoint);
 
       List<LibraryCycle> cycles = _logger.run('Compute library cycles', () {
         List<LibraryCycle> cycles = entryLibrary.topologicalOrder;
         _logger.writeln('Computed ${cycles.length} cycles.');
         return cycles;
       });
 
       CanonicalName nameRoot = new CanonicalName.root();
       DillTarget dillTarget = new DillTarget(
-          new Ticker(isVerbose: false), _uriTranslator, "vm_fasta",
-          flags: new TargetFlags(strongMode: _options.strongMode));
+          new Ticker(isVerbose: false),
+          _uriTranslator,
+          new VmFastaTarget(new TargetFlags(strongMode: _options.strongMode)));
 
       List<_LibraryCycleResult> results = [];
       await _logger.runAsync('Compute results for cycles', () async {
         for (LibraryCycle cycle in cycles) {
           _LibraryCycleResult result =
               await _compileCycle(nameRoot, dillTarget, cycle);
           results.add(result);
         }
       });
 
@@ skipping 191 matching lines @@
   /// TODO(scheglov) Use API signatures.
   /// TODO(scheglov) Or use tree shaking and compute signatures of outlines.
   final String signature;
 
   /// Kernel libraries for libraries in the [cycle].  Bodies of dependencies
   /// are not included, but but references to those dependencies are included.
   final List<Library> kernelLibraries;
 
   _LibraryCycleResult(this.cycle, this.signature, this.kernelLibraries);
 }