Spruce up iOS viewer and cut CPU drain

Main outcome here is that we only draw once per frame instead
of pinning the CPU. We also cut out a little extra traffic – an
autorelease pool per draw, but trivial. We also fix an overrelease
on NSProcessInfo.arguments, and a missing -init for the UIViewController

Change-Id: Ibb5ea5832bc65d2ff60351d4e3b76fd3b4ff88ee
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/337116
Commit-Queue: Adlai Holler <adlai@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
2 files changed