Still a hotspot but much improved.

Bug: angleproject:2786
Change-Id: Ie68ff314e6c952f281b48f6d9af37b5dcd194d6a
Reviewed-on: https://chromium-review.googlesource.com/1194882
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Frank Henigman <fjhenigman@chromium.org>