This prevents a multiply defined symbol error in ninja. Unforunately
I'm not aware of how to do the equivalent of GN's data_deps in GYP.

BUG=angleproject:1709

Change-Id: I9c616337c668a5fa652b6c084b2a64d83d526e4a
Reviewed-on: https://chromium-review.googlesource.com/437646Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>