NaCl-side GN changes to enable NaCl in Linux x64 Chrome builds.

src/shared/serialization/BUILD.gn

Index: src/shared/serialization/BUILD.gn
diff --git a/src/shared/serialization/BUILD.gn b/src/shared/serialization/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..c884a5f6bb08e7c208e2750cef599ed0dc299a12
--- /dev/null
+++ b/src/shared/serialization/BUILD.gn
@@ -0,0 +1,13 @@
+# Copyright (c) 2014 The Native ClientAuthors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//components/nacl/nacl_defines.gni")
+
+source_set("serialization") {
+  defines = nacl_defines
+  sources = [
+    "serialization.cc",
+    "serialization.h",
+  ]
+}