patch from chinmaygarde@ to make progress on mac, ios.
I've taken https://github.com/chinmaygarde/sky_engine/commit/
ad591c629a295936206dcfde37f63c8c82bc2838
and merged it onto Chromium ToT, with a few lint and other cleanups,
and one fix to make sure that Mac still compiled (which may have broken
iOS, haven't tested yet).
R=brettw@chromium.org, sdfresne@chromium.org
BUG=459705
CQ_EXTRA_TRYBOTS=tryserver.chromium.mac:mac_chromium_gn_rel,mac_chromium_gn_dbg
Review URL: https://codereview.chromium.org/
1250913002
Cr-Commit-Position: refs/heads/master@{#342297}