Prevent duplication of symbols in shared header file

This tools menu constants header file is moving to a public folder, but
has downstream dependencies. This change provides for both the new and
old path to reach the header.

Bug: 782936
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: Ia6de01254c025940c827e94216ce09ac82139c64
Reviewed-on: https://chromium-review.googlesource.com/772785
Reviewed-by: Sergio Collazos <sczs@chromium.org>
Commit-Queue: Peter Laurens <peterlaurens@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#517722}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 74f1e1ddc5a74cac5c2e110cf35abd94da255d89
2 files changed