fasta tokens implement analyzer token API

pkg/front_end/lib/src/fasta/scanner/abstract_scanner.dart

Index: pkg/front_end/lib/src/fasta/scanner/abstract_scanner.dart
diff --git a/pkg/front_end/lib/src/fasta/scanner/abstract_scanner.dart b/pkg/front_end/lib/src/fasta/scanner/abstract_scanner.dart
index 5e4f34518739517d5d057bd244bcaad369932c36..ad5c1bd34aaf0c2ff3eb36bb370e9555ba7d3e45 100644
--- a/pkg/front_end/lib/src/fasta/scanner/abstract_scanner.dart
+++ b/pkg/front_end/lib/src/fasta/scanner/abstract_scanner.dart
@@ -23,6 +23,14 @@ import 'token_constants.dart';
 
 import 'characters.dart';
 
+/**
+ * A constant flag indicating that fasta does not yet support generic method
+ * comments. This constant will be removed once support has been added.
+ * Any code that needs to be removed once support has been added
+ * should reference this flag.
+ */
+const bool fastaSupportsGenericMethodComments = false;
+
 abstract class AbstractScanner implements Scanner {
   final bool includeComments;