Add Go build support for GN.

mojo/go/BUILD.gn

Index: mojo/go/BUILD.gn
diff --git a/mojo/go/BUILD.gn b/mojo/go/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..3019775b2ea574ba392444497b51af755006225a
--- /dev/null
+++ b/mojo/go/BUILD.gn
@@ -0,0 +1,24 @@
+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//build/go/rules.gni")
+
+group("go") {
+  deps = [
+    ":system_test",
+  ]
+}
+
+go_test_binary("system_test") {
+  sources = [
+    "tests/system_test.go",
+  ]
+  additional_sources = [
+    "c_embedder/c_embedder.cc",
+    "c_embedder/c_embedder.h",
+  ]
+  deps = [
+    "//mojo/system",
+  ]
+}