diff -r 000000000000 -r 6474c204b198 dom/base/nsStructuredCloneContainer.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/base/nsStructuredCloneContainer.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,41 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sw=2 et 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 nsStructuredCloneContainer_h__
+#define nsStructuredCloneContainer_h__
+
+#include "nsIStructuredCloneContainer.h"
+#include "mozilla/Attributes.h"
+
+#define NS_STRUCTUREDCLONECONTAINER_CONTRACTID \
+  "@mozilla.org/docshell/structured-clone-container;1"
+#define NS_STRUCTUREDCLONECONTAINER_CID \
+{ /* 38bd0634-0fd4-46f0-b85f-13ced889eeec */       \
+  0x38bd0634,                                      \
+  0x0fd4,                                          \
+  0x46f0,                                          \
+  {0xb8, 0x5f, 0x13, 0xce, 0xd8, 0x89, 0xee, 0xec} \
+}
+
+class nsStructuredCloneContainer MOZ_FINAL : public nsIStructuredCloneContainer
+{
+  public:
+    nsStructuredCloneContainer();
+    ~nsStructuredCloneContainer();
+
+    NS_DECL_ISUPPORTS
+    NS_DECL_NSISTRUCTUREDCLONECONTAINER
+
+  private:
+    uint64_t* mData;
+
+    // This needs to be size_t rather than a PR-type so it matches the JS API.
+    size_t mSize;
+    uint32_t mVersion;
+};
+
+#endif