Add ifdef guard around gpu-specific code in native windows window.

Review URL: https://codereview.chromium.org/1405963014
diff --git a/AUTHORS b/AUTHORS
index 9d8e661..47f675b 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -37,3 +37,4 @@
 Thiago Fransosi Farina <thiago.farina@gmail.com>
 Jose Mayol <jei.mayol@gmail.com>
 Linaro <*@linaro.org>
+Christian Plesner Hansen <plesner@t.undra.org>