diff -r 000000000000 -r 6474c204b198 xpcom/ds/nsProperties.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xpcom/ds/nsProperties.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,116 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* 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/. */
+
+#include "nsProperties.h"
+
+////////////////////////////////////////////////////////////////////////////////
+
+NS_IMPL_AGGREGATED(nsProperties)
+NS_INTERFACE_MAP_BEGIN_AGGREGATED(nsProperties)
+    NS_INTERFACE_MAP_ENTRY(nsIProperties)
+NS_INTERFACE_MAP_END
+
+NS_IMETHODIMP
+nsProperties::Get(const char* prop, const nsIID & uuid, void* *result)
+{
+    if (NS_WARN_IF(!prop))
+        return NS_ERROR_INVALID_ARG;
+
+    nsCOMPtr<nsISupports> value;
+    if (!nsProperties_HashBase::Get(prop, getter_AddRefs(value))) {
+        return NS_ERROR_FAILURE;
+    }
+    return (value) ? value->QueryInterface(uuid, result) : NS_ERROR_NO_INTERFACE;
+}
+
+NS_IMETHODIMP
+nsProperties::Set(const char* prop, nsISupports* value)
+{
+    if (NS_WARN_IF(!prop))
+        return NS_ERROR_INVALID_ARG;
+    Put(prop, value);
+    return NS_OK;
+}
+
+NS_IMETHODIMP
+nsProperties::Undefine(const char* prop)
+{
+    if (NS_WARN_IF(!prop))
+        return NS_ERROR_INVALID_ARG;
+
+    nsCOMPtr<nsISupports> value;
+    if (!nsProperties_HashBase::Get(prop, getter_AddRefs(value)))
+        return NS_ERROR_FAILURE;
+
+    Remove(prop);
+    return NS_OK;
+}
+
+NS_IMETHODIMP
+nsProperties::Has(const char* prop, bool *result)
+{
+    if (NS_WARN_IF(!prop))
+        return NS_ERROR_INVALID_ARG;
+
+    nsCOMPtr<nsISupports> value;
+    *result = nsProperties_HashBase::Get(prop,
+                                         getter_AddRefs(value));
+    return NS_OK;
+}
+
+struct GetKeysEnumData
+{
+    char **keys;
+    uint32_t next;
+    nsresult res;
+};
+
+ PLDHashOperator
+GetKeysEnumerate(const char *key, nsISupports* data,
+                 void *arg)
+{
+    GetKeysEnumData *gkedp = (GetKeysEnumData *)arg;
+    gkedp->keys[gkedp->next] = strdup(key);
+
+    if (!gkedp->keys[gkedp->next]) {
+        gkedp->res = NS_ERROR_OUT_OF_MEMORY;
+        return PL_DHASH_STOP;
+    }
+
+    gkedp->next++;
+    return PL_DHASH_NEXT;
+}
+
+NS_IMETHODIMP 
+nsProperties::GetKeys(uint32_t *count, char ***keys)
+{
+    if (NS_WARN_IF(!count) || NS_WARN_IF(!keys))
+        return NS_ERROR_INVALID_ARG;
+
+    uint32_t n = Count();
+    char ** k = (char **) nsMemory::Alloc(n * sizeof(char *));
+
+    GetKeysEnumData gked;
+    gked.keys = k;
+    gked.next = 0;
+    gked.res = NS_OK;
+
+    EnumerateRead(GetKeysEnumerate, &gked);
+
+    nsresult rv = gked.res;
+    if (NS_FAILED(rv)) {
+        // Free 'em all
+        for (uint32_t i = 0; i < gked.next; i++)
+            nsMemory::Free(k[i]);
+        nsMemory::Free(k);
+        return rv;
+    }
+
+    *count = n;
+    *keys = k;
+    return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////