Add a centralized workarounds module. This is a temporary home for the various workarounds we use for performance or to solve driver issues. Eventually we will want a standalone library we can use as part of Chromium or in ANGLE standalone. Re-land with member variable initialized. BUG=angle:729 Change-Id: If7f8f9596a39b2855366d9a67caebf6dd4197b55 Reviewed-on: https://chromium-review.googlesource.com/219868 Tested-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org>