diff --git a/layout/base/FrameLayerBuilder.cpp b/layout/base/FrameLayerBuilder.cpp
index 9e5659fad085..5904215ad545 100644
--- a/layout/base/FrameLayerBuilder.cpp
+++ b/layout/base/FrameLayerBuilder.cpp
@@ -81,12 +81,12 @@ void
 FrameLayerBuilder::DisplayItemData::RemoveFrame(nsIFrame* aFrame)
 {
   MOZ_RELEASE_ASSERT(mLayer);
-  DebugOnly<bool> result = mFrameList.RemoveElement(aFrame);
-  NS_ASSERTION(result, "Can't remove a frame that wasn't added!");
+  bool result = mFrameList.RemoveElement(aFrame);
+  MOZ_RELEASE_ASSERT(result, "Can't remove a frame that wasn't added!");
 
   nsTArray<DisplayItemData*>* array =
     static_cast<nsTArray<DisplayItemData*>*>(aFrame->Properties().Get(FrameLayerBuilder::LayerManagerDataProperty()));
-  NS_ASSERTION(array, "Must be already stored on the frame!");
+  MOZ_RELEASE_ASSERT(array, "Must be already stored on the frame!");
   array->RemoveElement(this);
 }