Limit Mojo messages recursion depth

mojo/public/cpp/bindings/lib/validation_errors.h

Index: mojo/public/cpp/bindings/lib/validation_errors.h
diff --git a/mojo/public/cpp/bindings/lib/validation_errors.h b/mojo/public/cpp/bindings/lib/validation_errors.h
index 43db70c91df10b3bb9d79743829c15ef02f51892..1884d253f3ab126509a30b179cece1bdd4964d04 100644
--- a/mojo/public/cpp/bindings/lib/validation_errors.h
+++ b/mojo/public/cpp/bindings/lib/validation_errors.h
@@ -70,6 +70,9 @@ enum ValidationError {
   // Message deserialization failure, for example due to rejection by custom
   // validation logic.
   VALIDATION_ERROR_DESERIALIZATION_FAILED,
+  // The message contains a too deeply nested value, for example a recursively
+  // defined field which runtime value is too large.
+  VALIDATION_ERROR_MAX_RECURSION_DEPTH,
 };
 
 const char* ValidationErrorToString(ValidationError error);