--- a/layout/style/nsStyleStruct.h
+++ b/layout/style/nsStyleStruct.h
@@ -1052,16 +1052,18 @@ public:
     // actual array in one allocation. The amount of memory to
     // allocate is equal to the class's size + the number of bytes for all
     // but the first array item (because aBaseSize includes one
     // item, see the private declarations)
     return ::operator new(aBaseSize +
                           (aArrayLen - 1) * sizeof(nsCSSShadowItem));
   }
 
+  void operator delete(void* aPtr) { ::operator delete(aPtr); }
+
   explicit nsCSSShadowArray(uint32_t aArrayLen) :
     mLength(aArrayLen)
   {
     for (uint32_t i = 1; i < mLength; ++i) {
       // Make sure we call the constructors of each nsCSSShadowItem
       // (the first one is called for us because we declared it under private)
       new (&mArray[i]) nsCSSShadowItem();
     }