Roll engine to 6474647f5210a968d186901cc511153ec442e897 (with Dart roll)
diff --git a/bin/internal/engine.version b/bin/internal/engine.version
index 6c3d39a..073f86b 100644
--- a/bin/internal/engine.version
+++ b/bin/internal/engine.version
@@ -1 +1 @@
-eea6197a24256fe588e18127f56c733bc42b6a8d
+6474647f5210a968d186901cc511153ec442e897