Only display 'nits' in verbose mode.

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

Index: pkg/front_end/lib/src/fasta/messages.dart
diff --git a/pkg/front_end/lib/src/fasta/messages.dart b/pkg/front_end/lib/src/fasta/messages.dart
index d1f31aaa73b14a8d2a64a22aa809b6e806295a0f..4a2d96dfddf598298c417684c6af4575417e0e07 100644
--- a/pkg/front_end/lib/src/fasta/messages.dart
+++ b/pkg/front_end/lib/src/fasta/messages.dart
@@ -14,8 +14,6 @@ import 'errors.dart' show InputError;
 
 import 'colors.dart' show cyan, magenta;
 
-const bool hideNits = false;
-
 const bool hideWarnings = false;
 
 bool get errorsAreFatal => CompilerContext.current.options.errorsAreFatal;
@@ -26,6 +24,8 @@ bool get warningsAreFatal => CompilerContext.current.options.warningsAreFatal;
 
 bool get isVerbose => CompilerContext.current.options.verbose;
 
+bool get hideNits => !isVerbose;
+
 void warning(Uri uri, int charOffset, String message) {
   if (hideWarnings) return;
   print(format(uri, charOffset, colorWarning("Warning: $message")));