Migrate block 163 to Dart 2.0.

tests/language_2/unhandled_exception_negative_test.dart

Index: tests/language_2/unhandled_exception_negative_test.dart
diff --git a/tests/language/unhandled_exception_negative_test.dart b/tests/language_2/unhandled_exception_negative_test.dart
similarity index 91%
rename from tests/language/unhandled_exception_negative_test.dart
rename to tests/language_2/unhandled_exception_negative_test.dart
index f45091557a33e14680b24ce05336a073b3afa3ce..a91d1c727cb85e14eeb6d1a6bc695b20252c3fa8 100644
--- a/tests/language/unhandled_exception_negative_test.dart
+++ b/tests/language_2/unhandled_exception_negative_test.dart
@@ -4,7 +4,7 @@
 // Dart test program for testing unhandled exceptions.
 
 class MyException {
-  const MyException(String message = "") : message_ = message;
+  const MyException([String message = ""]) : message_ = message;

[Lasse Reichstein Nielsen, 2017/08/29 08:49:44]

Or make it non-optional, the parameter doesn't seem to be used as optional at
all.

[jcollins, 2017/08/29 17:39:11]

Done, and removing default.

   String getMessage() { return message_; }
   final String message_;
 }