Pass a Target instance to DillTarget instead of its name

pkg/front_end/lib/kernel_generator.dart

Index: pkg/front_end/lib/kernel_generator.dart
diff --git a/pkg/front_end/lib/kernel_generator.dart b/pkg/front_end/lib/kernel_generator.dart
index 248d13d447de9e5ec40a29f6af52f7b16fd4db33..e0ba4c782e326b5dcb2b06f745b1e2e2acdbd823 100644
--- a/pkg/front_end/lib/kernel_generator.dart
+++ b/pkg/front_end/lib/kernel_generator.dart
@@ -14,6 +14,7 @@ import 'src/fasta/errors.dart' show InputError;
 import 'src/fasta/kernel/kernel_target.dart' show KernelTarget;
 import 'package:kernel/kernel.dart' show Program;
 import 'package:kernel/target/targets.dart' show TargetFlags;
+import 'package:kernel/target/vm_fasta.dart' show VmFastaTarget;
 import 'src/fasta/ticker.dart' show Ticker;
 import 'src/fasta/translate_uri.dart' show TranslateUri;
 import 'src/simple_error.dart';
@@ -53,9 +54,8 @@ Future<Program> kernelForProgram(Uri source, CompilerOptions options) async {
   try {
     TranslateUri uriTranslator = await pOptions.getUriTranslator();
 
-    var dillTarget = new DillTarget(
-        new Ticker(isVerbose: false), uriTranslator, "vm_fasta",
-        flags: new TargetFlags(strongMode: options.strongMode));
+    var dillTarget = new DillTarget(new Ticker(isVerbose: false), uriTranslator,
+        new VmFastaTarget(new TargetFlags(strongMode: options.strongMode)));
     var summary = await pOptions.sdkSummaryProgram;
     if (summary != null) {
       dillTarget.loader.appendLibraries(summary);
@@ -150,9 +150,8 @@ Future<Program> kernelForBuildUnit(
   try {
     TranslateUri uriTranslator = await pOptions.getUriTranslator();
 
-    var dillTarget = new DillTarget(
-        new Ticker(isVerbose: false), uriTranslator, "vm_fasta",
-        flags: new TargetFlags(strongMode: options.strongMode));
+    var dillTarget = new DillTarget(new Ticker(isVerbose: false), uriTranslator,
+        new VmFastaTarget(new TargetFlags(strongMode: options.strongMode)));
     var summary = await pOptions.sdkSummaryProgram;
     if (summary != null) {
       dillTarget.loader.appendLibraries(summary);