diff -r 000000000000 -r 6474c204b198 dom/quota/Utilities.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/quota/Utilities.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,36 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* 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 mozilla_dom_quota_utilities_h__
+#define mozilla_dom_quota_utilities_h__
+
+#include "mozilla/dom/quota/QuotaCommon.h"
+
+BEGIN_QUOTA_NAMESPACE
+
+inline void
+IncrementUsage(uint64_t* aUsage, uint64_t aDelta)
+{
+  // Watch for overflow!
+  if ((UINT64_MAX - *aUsage) < aDelta) {
+    NS_WARNING("Usage exceeds the maximum!");
+    *aUsage = UINT64_MAX;
+  }
+  else {
+    *aUsage += aDelta;
+  }
+}
+
+inline bool
+PatternMatchesOrigin(const nsACString& aPatternString, const nsACString& aOrigin)
+{
+  // Aren't we smart!
+  return StringBeginsWith(aOrigin, aPatternString);
+}
+
+END_QUOTA_NAMESPACE
+
+#endif // mozilla_dom_quota_utilities_h__