Remove iOS 10 only code.

Removes the POST request workaround and a few |IsRunningOnIOS11OrLater|
checks.

Bug: 740987, 872818
Change-Id: Ia6258eb24aaff0c0b92a4be9d85ddbe501f872a6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1537321
Auto-Submit: Mike Dougherty <michaeldo@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Commit-Queue: Mike Dougherty <michaeldo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#644120}
11 files changed