Convert all iOS service manifests to C++

Removes usage of deprecated JSON service manifests and overlays from
//ios and replaces them with C++ Manifest objects.

Bug: 895616
Change-Id: Ie55c1dfe0a1d960c1d83206fdc6e1e540e1cdefb
Reviewed-on: https://chromium-review.googlesource.com/c/1416094
Commit-Queue: Ken Rockot <rockot@google.com>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#623803}
31 files changed