This is a reland of bedb69ccfb
Original change's description:
> Clean up #includes in SkCFObject.
>
> SKCFObject.h wasn't compiling without prefixing it with other includes,
> so adding them into the actual file itself. Also changed to use the
> more generic __APPLE__ as a guard rather than BUILD_FOR_MAC or
> BUILD_FOR_IOS defines, and added the file to BUILD.gn so it will be
> added to Xcode projects.
>
> Change-Id: I67a48d0156ef1eb5c69dd045f0acadf147053eb6
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/455163
> Auto-Submit: Jim Van Verth <jvanverth@google.com>
> Commit-Queue: Brian Osman <brianosman@google.com>
> Reviewed-by: Brian Osman <brianosman@google.com>
Change-Id: Ibf372fc07c78121beae8cd78e0a8a9f4a6d7ef5d
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/455998
Commit-Queue: Jim Van Verth <jvanverth@google.com>
Auto-Submit: Jim Van Verth <jvanverth@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
37c4976947