Pass a Target instance to DillTarget instead of its name

pkg/front_end/lib/src/incremental_kernel_generator_impl.dart

Index: pkg/front_end/lib/src/incremental_kernel_generator_impl.dart
diff --git a/pkg/front_end/lib/src/incremental_kernel_generator_impl.dart b/pkg/front_end/lib/src/incremental_kernel_generator_impl.dart
index 849b81af048a2951858acaff202290889f7270fd..c6653299d58d6ea1695e71f29c5db6bf45f7d9c4 100644
--- a/pkg/front_end/lib/src/incremental_kernel_generator_impl.dart
+++ b/pkg/front_end/lib/src/incremental_kernel_generator_impl.dart
@@ -21,6 +21,7 @@ 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.
@@ -102,8 +103,9 @@ class IncrementalKernelGeneratorImpl implements IncrementalKernelGenerator {
 
       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 {