Changed out the crate for interfacing with CoreGraphics types.

[rizerco]

This is to get round App Store submission issues. The new crate is one that I’ve just published myself, so it’s understandable if you don’t want to accept this PR, but I thought I’d submit it anyway for your consideration.

This is the issue I see when trying to upload to the App Store without this fix:

ITMS-90338: Non-public API usage - The app references non-public symbols in Frameworks/framework_name.framework/framework_name: _CGContextSetFontSmoothingStyle. If method names in your source code match the private Apple APIs listed above, altering your method names will help prevent this app from being flagged in future submissions. In addition, note that one or more of the above APIs may be located in a static library that was included with your app. If so, they must be removed. For further information, visit the Technical Support Information at http://developer.apple.com/support/technical/

Let me know if you have any questions.

Thanks!

[jinleili]

Thank you for your pull request. I have also submitted Apps to the App Store, and I haven't encountered similar issues so far, although that was a year ago. I might be more inclined to use the objc2 because it is very likely that wgpu will switch to using objc2 in the near future to replace metal-rs and other crates for Apple platforms.

[waywardmonkeys]

We just got a bug report about this and a PR upstream, so we will resolve it soon: servo/core-foundation-rs#708