diff -r 000000000000 -r 6474c204b198 xpcom/glue/nsCycleCollectionNoteChild.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xpcom/glue/nsCycleCollectionNoteChild.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,88 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This header will be included by headers that define refpointer and array classes
+// in order to specialize CC helpers such as ImplCycleCollectionTraverse for them.
+
+#ifndef nsCycleCollectionNoteChild_h__
+#define nsCycleCollectionNoteChild_h__
+
+#include "nsCycleCollectionTraversalCallback.h"
+#include "mozilla/Likely.h"
+#include "mozilla/TypeTraits.h"
+
+enum {
+  CycleCollectionEdgeNameArrayFlag = 1
+};
+
+// Just a helper for appending "[i]". Didn't want to pull in string headers here.
+void
+CycleCollectionNoteEdgeNameImpl(nsCycleCollectionTraversalCallback& aCallback,
+                                const char* aName,
+                                uint32_t aFlags = 0);
+
+// Should be inlined so that in the no-debug-info case this is just a simple if().
+MOZ_ALWAYS_INLINE void
+CycleCollectionNoteEdgeName(nsCycleCollectionTraversalCallback& aCallback,
+                            const char* aName,
+                            uint32_t aFlags = 0)
+{
+  if (MOZ_UNLIKELY(aCallback.WantDebugInfo())) {
+    CycleCollectionNoteEdgeNameImpl(aCallback, aName, aFlags);
+  }
+}
+
+#define NS_CYCLE_COLLECTION_INNERCLASS                                         \
+        cycleCollection
+
+#define NS_CYCLE_COLLECTION_INNERNAME                                          \
+        _cycleCollectorGlobal
+
+#define NS_CYCLE_COLLECTION_PARTICIPANT(_class)                                \
+        _class::NS_CYCLE_COLLECTION_INNERCLASS::GetParticipant()
+
+template <typename T>
+nsISupports* ToSupports(T* p, typename T::NS_CYCLE_COLLECTION_INNERCLASS* dummy = 0)
+{
+  return T::NS_CYCLE_COLLECTION_INNERCLASS::Upcast(p);
+}
+
+// The default implementation of this class template is empty, because it
+// should never be used: see the partial specializations below.
+template <typename T,
+          bool IsXPCOM = mozilla::IsBaseOf<nsISupports, T>::value>
+struct CycleCollectionNoteChildImpl
+{
+};
+
+template <typename T>
+struct CycleCollectionNoteChildImpl<T, true>
+{
+  static void Run(nsCycleCollectionTraversalCallback& aCallback, T* aChild)
+  {
+    aCallback.NoteXPCOMChild(ToSupports(aChild));
+  }
+};
+
+template <typename T>
+struct CycleCollectionNoteChildImpl<T, false>
+{
+  static void Run(nsCycleCollectionTraversalCallback& aCallback, T* aChild)
+  {
+    aCallback.NoteNativeChild(aChild, NS_CYCLE_COLLECTION_PARTICIPANT(T));
+  }
+};
+
+template <typename T>
+inline void CycleCollectionNoteChild(nsCycleCollectionTraversalCallback& aCallback,
+                                     T* aChild,
+                                     const char* aName,
+                                     uint32_t aFlags = 0)
+{
+  CycleCollectionNoteEdgeName(aCallback, aName, aFlags);
+  CycleCollectionNoteChildImpl<T>::Run(aCallback, aChild);
+}
+
+#endif // nsCycleCollectionNoteChild_h__