diff -r 000000000000 -r 6474c204b198 accessible/src/base/nsAccCache.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/accessible/src/base/nsAccCache.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,81 @@
+/* -*- 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/. */
+
+#ifndef _nsAccCache_H_
+#define _nsAccCache_H_
+
+#include "nsIAccessible.h"
+#include "nsRefPtrHashtable.h"
+#include "nsCycleCollectionParticipant.h"
+
+////////////////////////////////////////////////////////////////////////////////
+// Accessible cache utils
+////////////////////////////////////////////////////////////////////////////////
+
+/**
+ * Shutdown and removes the accessible from cache.
+ */
+template <class T>
+static PLDHashOperator
+ClearCacheEntry(const void* aKey, nsRefPtr<T>& aAccessible, void* aUserArg)
+{
+  NS_ASSERTION(aAccessible, "Calling ClearCacheEntry with a nullptr pointer!");
+  if (aAccessible)
+    aAccessible->Shutdown();
+
+  return PL_DHASH_REMOVE;
+}
+
+/**
+ * Clear the cache and shutdown the accessibles.
+ */
+
+static void
+ClearCache(mozilla::a11y::AccessibleHashtable& aCache)
+{
+  aCache.Enumerate(ClearCacheEntry<mozilla::a11y::Accessible>, nullptr);
+}
+
+/**
+ * Traverse the accessible cache entry for cycle collector.
+ */
+template <class T>
+static PLDHashOperator
+CycleCollectorTraverseCacheEntry(const void *aKey, T *aAccessible,
+                                 void *aUserArg)
+{
+  nsCycleCollectionTraversalCallback *cb =
+    static_cast<nsCycleCollectionTraversalCallback*>(aUserArg);
+
+  NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(*cb, "accessible cache entry");
+
+  nsISupports *supports = static_cast<nsIAccessible*>(aAccessible);
+  cb->NoteXPCOMChild(supports);
+  return PL_DHASH_NEXT;
+}
+
+/**
+ * Unlink the accessible cache for the cycle collector.
+ */
+inline void
+ImplCycleCollectionUnlink(mozilla::a11y::AccessibleHashtable& aCache)
+{
+  ClearCache(aCache);
+}
+
+/**
+ * Traverse the accessible cache for cycle collector.
+ */
+inline void
+ImplCycleCollectionTraverse(nsCycleCollectionTraversalCallback& aCallback,
+                            mozilla::a11y::AccessibleHashtable& aCache,
+                            const char* aName,
+                            uint32_t aFlags = 0)
+{
+  aCache.EnumerateRead(CycleCollectorTraverseCacheEntry<mozilla::a11y::Accessible>,
+                       &aCallback);
+}
+
+#endif