diff --git a/xpcom/glue/nsInterfaceHashtable.h b/xpcom/glue/nsInterfaceHashtable.h
index 14368af63..fbd5c9238 100644
--- a/xpcom/glue/nsInterfaceHashtable.h
+++ b/xpcom/glue/nsInterfaceHashtable.h
@@ -53,6 +53,21 @@ public:
    * @return The entry, or nullptr if not found. Do not release this pointer!
    */
   Interface* GetWeak(KeyType aKey, bool* aFound = nullptr) const;
+
+  /**
+   * Allows inserting a value into the hashtable, moving its owning reference
+   * count into the hashtable, avoiding an AddRef.
+   */
+  void Put(KeyType aKey, already_AddRefed<Interface>&& aData)
+  {
+    if (!Put(aKey, mozilla::Move(aData), mozilla::fallible)) {
+      NS_ABORT_OOM(this->mTable.EntrySize() * this->mTable.EntryCount());
+    }
+  }
+
+  MOZ_MUST_USE bool Put(KeyType aKey, already_AddRefed<Interface>&& aData,
+                        const mozilla::fallible_t&);
+  using base_type::Put;
 };
 
 template<typename K, typename T>
@@ -139,4 +154,19 @@ nsInterfaceHashtable<KeyClass, Interface>::GetWeak(KeyType aKey,
   return nullptr;
 }
 
+template<class KeyClass, class Interface>
+bool
+nsInterfaceHashtable<KeyClass, Interface>::Put(KeyType aKey,
+                                               already_AddRefed<Interface>&& aValue,
+                                               const mozilla::fallible_t&)
+{
+  typename base_type::EntryType* ent = this->PutEntry(aKey);
+  if (!ent) {
+    return false;
+  }
+
+  ent->mData = aValue;
+  return true;
+}
+
 #endif // nsInterfaceHashtable_h__