The lexer was missing some recent changes.

BUG=angle:593

Change-Id: I8fa598e5a4ae35ebc9f9a48789632b6a326bc4d3
Reviewed-on: https://chromium-review.googlesource.com/194136Reviewed-by: Nicolas Capens <nicolascapens@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>