Add GN build file for ui/aura target.

ui/gfx/x/BUILD.gn

Index: ui/gfx/x/BUILD.gn
diff --git a/ui/gfx/x/BUILD.gn b/ui/gfx/x/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..d7ae7ed4ab94d8572dd158004e72929ee2fba5e0
--- /dev/null
+++ b/ui/gfx/x/BUILD.gn
@@ -0,0 +1,32 @@
+# 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.
+
+component("x") {
+  output_name = "gfx_x11"

[jamesr, 2014/06/21 00:41:09]

hmm, there's been a ui/gfx/BUILD.gn:gfx_x11 target for a while now. which do we
want?

[brettw, 2014/06/21 00:46:35]

I think this one is better. We should always be having BUILD files closer to the
files.

+
+  sources = [
+    "x11_atom_cache.cc",
+    "x11_atom_cache.h",
+    "x11_connection.cc",
+    "x11_connection.h",
+    "x11_error_tracker.cc",
+    "x11_error_tracker.h",
+    "x11_switches.cc",
+    "x11_switches.h",
+    "x11_types.cc",
+    "x11_types.h",
+  ]
+
+  defines = [
+    "GFX_IMPLEMENTATION",
+  ]
+
+  configs += [
+    "//build/config/linux:x11",
+  ]
+
+  deps = [
+    "//base",
+  ]
+}