--- a/js/src/vm/NativeObject.h
+++ b/js/src/vm/NativeObject.h
@@ -1123,16 +1123,20 @@ class NativeObject : public ShapedObject
 
     inline void setShouldConvertDoubleElements();
     inline void clearShouldConvertDoubleElements();
 
     bool denseElementsAreCopyOnWrite() {
         return getElementsHeader()->isCopyOnWrite();
     }
 
+    bool denseElementsAreFrozen() {
+        return getElementsHeader()->isFrozen();
+    }
+
     /* Packed information for this object's elements. */
     inline bool writeToIndexWouldMarkNotPacked(uint32_t index);
     inline void markDenseElementsNotPacked(ExclusiveContext* cx);
 
     // Ensures that the object can hold at least index + extra elements. This
     // returns DenseElement_Success on success, DenseElement_Failed on failure
     // to grow the array, or DenseElement_Incomplete when the object is too
     // sparse to grow (this includes the case of index + extra overflow). In