fasta.CommentToken implement analyzer.CommentToken

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

Index: pkg/front_end/lib/src/fasta/scanner/string_scanner.dart
diff --git a/pkg/front_end/lib/src/fasta/scanner/string_scanner.dart b/pkg/front_end/lib/src/fasta/scanner/string_scanner.dart
index a7ac73b27a567fd9e2c3c1358e34e491e06aaecf..af35b011fcf60e5618ef3e6f6ef87ce94da9ca3d 100644
--- a/pkg/front_end/lib/src/fasta/scanner/string_scanner.dart
+++ b/pkg/front_end/lib/src/fasta/scanner/string_scanner.dart
@@ -8,7 +8,7 @@ import 'array_based_scanner.dart' show ArrayBasedScanner;
 
 import 'precedence.dart' show PrecedenceInfo;
 
-import 'token.dart' show StringToken;
+import 'token.dart' show CommentToken, DartDocToken, StringToken;
 
 /**
  * Scanner that reads from a String and creates tokens that points to
@@ -50,5 +50,23 @@ class StringScanner extends ArrayBasedScanner {
         canonicalize: true);
   }
 
+  @override
+  CommentToken createCommentToken(
+      PrecedenceInfo info, int start, bool asciiOnly,
+      [int extraOffset = 0]) {
+    return new CommentToken.fromSubstring(
+        info, string, start, scanOffset + extraOffset, tokenStart,
+        canonicalize: true);
+  }
+
+  @override
+  DartDocToken createDartDocToken(
+      PrecedenceInfo info, int start, bool asciiOnly,
+      [int extraOffset = 0]) {
+    return new DartDocToken.fromSubstring(
+        info, string, start, scanOffset + extraOffset, tokenStart,
+        canonicalize: true);
+  }
+
   bool atEndOfFile() => scanOffset >= string.length - 1;
 }