Prepare for separate setter scope.

pkg/front_end/lib/src/fasta/dill/dill_target.dart

Index: pkg/front_end/lib/src/fasta/dill/dill_target.dart
diff --git a/pkg/front_end/lib/src/fasta/dill/dill_target.dart b/pkg/front_end/lib/src/fasta/dill/dill_target.dart
index 70629fb1b1786e8067350bad517c74ed03ae5aae..4e53c689b4a8f9b47f3d53314330587d58b78401 100644
--- a/pkg/front_end/lib/src/fasta/dill/dill_target.dart
+++ b/pkg/front_end/lib/src/fasta/dill/dill_target.dart
@@ -18,7 +18,7 @@ import '../ticker.dart' show Ticker;
 
 import '../translate_uri.dart' show TranslateUri;
 
-import '../kernel/kernel_builder.dart' show ClassBuilder, KernelClassBuilder;
+import '../kernel/kernel_builder.dart' show ClassBuilder;
 
 import 'dill_library_builder.dart' show DillLibraryBuilder;
 
@@ -67,8 +67,5 @@ class DillTarget extends TargetImplementation {
 
   void breakCycle(ClassBuilder cls) {}
 
-  Class get objectClass {
-    KernelClassBuilder builder = loader.coreLibrary.exports["Object"];
-    return builder.cls;
-  }
+  Class get objectClass => loader.coreLibrary["Object"].target;
 }