Remove deprecated_addNit.

pkg/front_end/lib/src/fasta/builder/library_builder.dart

Index: pkg/front_end/lib/src/fasta/builder/library_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/builder/library_builder.dart b/pkg/front_end/lib/src/fasta/builder/library_builder.dart
index 5dbaa438f39d671b631cfa509e752e1cd39f1793..4eedc7ab95c27f9670f779ad9679efebb17c7781 100644
--- a/pkg/front_end/lib/src/fasta/builder/library_builder.dart
+++ b/pkg/front_end/lib/src/fasta/builder/library_builder.dart
@@ -15,7 +15,6 @@ import '../loader.dart' show Loader;
 import '../messages.dart'
     show
         Message,
-        deprecated_nit,
         deprecated_warning,
         nit,
         templateInternalProblemConstructorNotFound,
@@ -116,14 +115,6 @@ abstract class LibraryBuilder<T extends TypeBuilder, R> extends Builder {
     }
   }
 
-  void deprecated_addNit(int charOffset, Object message,
-      {Uri fileUri, bool silent: false}) {
-    fileUri ??= this.fileUri;
-    if (!silent) {
-      deprecated_nit(fileUri, charOffset, message);
-    }
-  }
-
   /// Returns true if the export scope was modified.
   bool addToExportScope(String name, Builder member) {
     if (name.startsWith("_")) return false;