Create a StructuredCloneData struct to encapsulate the result of a structured clone.

components/script/dom/bindings/structuredclone.rs

@@ -0,0 +1,12 @@
+/* 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/. */
+
+use libc::size_t;
+
+#[allow(raw_pointer_deriving)]
+#[deriving(Copy)]
+pub struct StructuredCloneData {
+    pub data: *mut u64,
+    pub nbytes: size_t,
+}