Used to crash on arm because of unaligned float access in positionColorData

BUG=chromium:675997

Change-Id: Iadc705986700248ce3cff9bb33fcd72c94ad1c59
Reviewed-on: https://chromium-review.googlesource.com/764688Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Yuly Novikov <ynovikov@chromium.org>