cleanup fasta token classes

pkg/front_end/lib/src/fasta/kernel/body_builder.dart

Index: pkg/front_end/lib/src/fasta/kernel/body_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/kernel/body_builder.dart b/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
index cb1c09b6b3e6d6c1f19f7fc3aaefe4c3064e9c5d..73b8638cb7a360b6e3bcfe84264a0eda8bd6082a 100644
--- a/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
@@ -36,10 +36,9 @@ import 'package:kernel/core_types.dart' show CoreTypes;
 
 import 'frontend_accessors.dart' show buildIsNull, makeBinary, makeLet;
 
-import '../../scanner/token.dart' show Token;
+import '../../scanner/token.dart' show BeginToken, Token;
 
-import '../scanner/token.dart'
-    show BeginGroupToken, isBinaryOperator, isMinusOperator;
+import '../scanner/token.dart' show isBinaryOperator, isMinusOperator;
 
 import '../errors.dart' show InputError, formatUnexpected, internalError;
 
@@ -584,7 +583,7 @@ class BodyBuilder extends ScopeListener<JumpTarget> implements BuilderHelper {
   }
 
   @override
-  void handleParenthesizedExpression(BeginGroupToken token) {
+  void handleParenthesizedExpression(BeginToken token) {
     debugEvent("ParenthesizedExpression");
     push(new ParenthesizedExpression(this, popForValue(), token.endGroup));
   }