diff --git a/engine/src/flutter/build/flutter_app.gni b/engine/src/flutter/build/flutter_app.gni
index 65157d147b..a25b1511c2 100644
--- a/engine/src/flutter/build/flutter_app.gni
+++ b/engine/src/flutter/build/flutter_app.gni
@@ -27,7 +27,7 @@ template("flutter_app") {
   dart_package_name = target_name + "_dart_package"
 
   dart_package(dart_package_name) {
-    forward_variables_from(invoker, [ "deps" ])
+    forward_variables_from(invoker, [ "deps", "source_dir" ])
     if (defined(invoker.package_name)) {
       package_name = invoker.package_name
     } else {