Revert "Add support for the new function-type syntax."

pkg/compiler/lib/src/parser/diet_parser_task.dart

Index: pkg/compiler/lib/src/parser/diet_parser_task.dart
diff --git a/pkg/compiler/lib/src/parser/diet_parser_task.dart b/pkg/compiler/lib/src/parser/diet_parser_task.dart
index 03a82220e3702d5e91394a6584d364d25a78b11b..d987f5773878b324229667cdec2e886a8a0a211c 100644
--- a/pkg/compiler/lib/src/parser/diet_parser_task.dart
+++ b/pkg/compiler/lib/src/parser/diet_parser_task.dart
@@ -17,9 +17,7 @@ import 'package:front_end/src/fasta/parser.dart'
 class PartialParser extends TopLevelParser {
   PartialParser(Listener listener) : super(listener);
 
-  Token parseFormalParameters(Token token, {bool inFunctionType: false}) {
-    return skipFormalParameters(token);
-  }
+  Token parseFormalParameters(Token token) => skipFormalParameters(token);
 }
 
 class DietParserTask extends CompilerTask {