Report messages instead of just printing.

pkg/front_end/lib/src/fasta/target_implementation.dart

Index: pkg/front_end/lib/src/fasta/target_implementation.dart
diff --git a/pkg/front_end/lib/src/fasta/target_implementation.dart b/pkg/front_end/lib/src/fasta/target_implementation.dart
index 200f4d619409e104749927806e8403bc365c5c1e..338380d5f2fc77d32cb9a39f4c2f0be57fe4c0db 100644
--- a/pkg/front_end/lib/src/fasta/target_implementation.dart
+++ b/pkg/front_end/lib/src/fasta/target_implementation.dart
@@ -8,6 +8,8 @@ import 'package:kernel/target/targets.dart' as backend show Target;
 
 import 'builder/builder.dart' show Builder, ClassBuilder, LibraryBuilder;
 
+import 'compiler_context.dart' show CompilerContext;
+
 import 'loader.dart' show Loader;
 
 import 'target.dart' show Target;
@@ -22,6 +24,8 @@ abstract class TargetImplementation extends Target {
 
   final backend.Target backendTarget;
 
+  final CompilerContext context = CompilerContext.current;
+
   Builder cachedAbstractClassInstantiationError;
   Builder cachedCompileTimeError;
   Builder cachedDuplicatedFieldInitializerError;