Fix bug with using enums as default values in mojom. We were previously

mojo/public/bindings/tests/sample_import2.mojom

Index: mojo/public/bindings/tests/sample_import2.mojom
diff --git a/mojo/public/bindings/tests/sample_import2.mojom b/mojo/public/bindings/tests/sample_import2.mojom
index 07c80f0d6bff104590376a3a847022a652424c9b..32be752b7244d440c06d201e6a3a455005184d04 100644
--- a/mojo/public/bindings/tests/sample_import2.mojom
+++ b/mojo/public/bindings/tests/sample_import2.mojom
@@ -20,8 +20,8 @@ struct Size {
 };
 
 struct Thing {
-  int32 shape;
-  int32 color;
+  int32 shape = SHAPE_RECTANGLE;
+  int32 color = COLOR_BLACK;
   Point location = {0, 0};
   Size size;
 };