diff -r 000000000000 -r 6474c204b198 xpcom/base/nsVersionComparatorImpl.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xpcom/base/nsVersionComparatorImpl.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,19 @@
+/* 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 "nsVersionComparatorImpl.h"
+#include "nsVersionComparator.h"
+#include "nsString.h"
+
+NS_IMPL_ISUPPORTS(nsVersionComparatorImpl, nsIVersionComparator)
+
+NS_IMETHODIMP
+nsVersionComparatorImpl::Compare(const nsACString& A, const nsACString& B,
+				 int32_t *aResult)
+{
+  *aResult = mozilla::CompareVersions(PromiseFlatCString(A).get(),
+				      PromiseFlatCString(B).get());
+
+  return NS_OK;
+}