cleanup fasta token classes

pkg/front_end/lib/src/fasta/source/diet_listener.dart

Index: pkg/front_end/lib/src/fasta/source/diet_listener.dart
diff --git a/pkg/front_end/lib/src/fasta/source/diet_listener.dart b/pkg/front_end/lib/src/fasta/source/diet_listener.dart
index ee46b5b1861fc5f6a2959a4f6625f3efa2aa8cce..520308bb8309383372c81ebad943538f971d1ad8 100644
--- a/pkg/front_end/lib/src/fasta/source/diet_listener.dart
+++ b/pkg/front_end/lib/src/fasta/source/diet_listener.dart
@@ -20,9 +20,7 @@ import '../fasta_codes.dart' show FastaMessage, codeExpectedBlockToSkip;
 
 import '../parser/parser.dart' show MemberKind, Parser, optional;
 
-import '../scanner/token.dart' show BeginGroupToken;
-
-import '../../scanner/token.dart' show Token;
+import '../../scanner/token.dart' show BeginToken, Token;
 
 import '../parser/dart_vm_native.dart' show removeNativeClause;
 
@@ -367,7 +365,7 @@ class DietListener extends StackListener {
   void endFactoryMethod(
       Token beginToken, Token factoryKeyword, Token endToken) {
     debugEvent("FactoryMethod");
-    BeginGroupToken bodyToken = pop();
+    BeginToken bodyToken = pop();
     String name = pop();
     checkEmpty(beginToken.charOffset);
     if (bodyToken == null || optional("=", bodyToken.endGroup.next)) {