--- a/accessible/ipc/DocAccessibleParent.h
+++ b/accessible/ipc/DocAccessibleParent.h
@@ -118,16 +118,20 @@ public:
 
     ProxyEntry* e = mAccessibles.GetEntry(aID);
     return e ? e->mProxy : nullptr;
   }
 
   const ProxyAccessible* GetAccessible(uintptr_t aID) const
     { return const_cast<DocAccessibleParent*>(this)->GetAccessible(aID); }
 
+  size_t ChildDocCount() const { return mChildDocs.Length(); }
+  const DocAccessibleParent* ChildDocAt(size_t aIdx) const
+    { return mChildDocs[aIdx]; }
+
 private:
 
   class ProxyEntry : public PLDHashEntryHdr
   {
   public:
     explicit ProxyEntry(const void*) : mProxy(nullptr) {}
     ProxyEntry(ProxyEntry&& aOther) :
       mProxy(aOther.mProxy) { aOther.mProxy = nullptr; }