Support for --fatal-hints.

test/options_test.dart

Index: test/options_test.dart
diff --git a/test/options_test.dart b/test/options_test.dart
index a495b8ecb2a8ea9371cfb33f8ed07f48077a1b5c..93f37e483d204a17827bb4cf3d6f5a3b19d2062b 100644
--- a/test/options_test.dart
+++ b/test/options_test.dart
@@ -23,6 +23,7 @@ main() {
         expect(options.enableStrictCallChecks, isFalse);
         expect(options.enableSuperMixins, isFalse);
         expect(options.enableTypeChecks, isFalse);
+        expect(options.hintsAreFatal, isFalse);
         expect(options.ignoreUnrecognizedFlags, isFalse);
         expect(options.log, isFalse);
         expect(options.machineFormat, isFalse);
@@ -66,6 +67,12 @@ main() {
         expect(options.enableTypeChecks, isTrue);
       });
 
+      test('hintsAreFatal', () {
+        CommandLineOptions options = CommandLineOptions
+            .parse(['--dart-sdk', '.', '--fatal-hints', 'foo.dart']);
+        expect(options.hintsAreFatal, isTrue);
+      });
+
       test('log', () {
         CommandLineOptions options =
             CommandLineOptions.parse(['--dart-sdk', '.', '--log', 'foo.dart']);