IWYU fixes in /rlz.

base/win/registry.h includes more than it uses. These files were
inadvertently relying on that fact. This CL adds missing includes so
that registry.h can be cleaned up.

BUG=None
This CL was uploaded by git cl split.

R=sdefresne@chromium.org

Change-Id: Ia84a3141bc4b84c6ced69dba12784cb448b2091c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2474694
Auto-Submit: Greg Thompson <grt@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#817441}

rlz/test/rlz_test_helpers.cc

@@ -12,6 +12,7 @@
 #include <map>
 #include <vector>
 
+#include "base/notreached.h"
 #include "base/strings/string16.h"
 #include "build/build_config.h"
 #include "rlz/lib/rlz_lib.h"