1 files changed, 11 insertions, 0 deletions
diff --git a/components/layout/flow.rs b/components/layout/flow.rs
index 3da277d924d..fae309d2ae2 100644
--- a/components/layout/flow.rs
+++ b/components/layout/flow.rs
@@ -30,6 +30,7 @@ use block::{BlockFlow, FormattingContextType};
 use context::{LayoutContext, SharedLayoutContext};
 use display_list_builder::DisplayListBuildState;
 use euclid::{Point2D, Size2D};
+use flex::FlexFlow;
 use floats::{Floats, SpeculatedFloatPlacement};
 use flow_list::{FlowList, MutFlowListIterator};
 use flow_ref::{FlowRef, WeakFlowRef};
@@ -86,6 +87,16 @@ pub trait Flow: fmt::Debug + Sync + Send + 'static {
         panic!("called as_mut_block() on a non-block flow")
     }
 
+    /// If this is a flex flow, returns the underlying object. Fails otherwise.
+    fn as_flex(&self) -> &FlexFlow {
+        panic!("called as_flex() on a non-flex flow")
+    }
+
+    /// If this is a flex flow, returns the underlying object, borrowed mutably. Fails otherwise.
+    fn as_mut_flex(&mut self) -> &mut FlexFlow {
+        panic!("called as_mut_flex() on a non-flex flow")
+    }
+
     /// If this is an inline flow, returns the underlying object. Fails otherwise.
     fn as_inline(&self) -> &InlineFlow {
         panic!("called as_inline() on a non-inline flow")