policy: drop unused gtest include

This file doesn't use FRIEND_TEST, so drop the header.

BUG=chromium:359322
TEST=`emerge-link platform2` still works
TEST=`FEATURES=test emerge-link platform2` still works

Change-Id: I99f3c13c7cea9bd85090fbc6c63c84a298754a7f
Reviewed-on: https://chromium-review.googlesource.com/193030
Reviewed-by: Liam McLoughlin <lmcloughlin@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
diff --git a/chromeos/policy/libpolicy.h b/chromeos/policy/libpolicy.h
index 2d07147..3e10544 100644
--- a/chromeos/policy/libpolicy.h
+++ b/chromeos/policy/libpolicy.h
@@ -5,7 +5,6 @@
 #ifndef POLICY_LIBPOLICY_H_
 #define POLICY_LIBPOLICY_H_
 
-#include <gtest/gtest_prod.h>
 #include <string>
 
 #include <base/basictypes.h>