998761eb14
Migrates Objective-C code in shell/gpu to ARC. Migrate `sk_cfp::reset(__bridge_retained ptr)` to `sk_cfp::retain(__bridge ptr)`. `reset` `CFRelease`s the previously held pointer and sets the pointer to the new pointer. `retain` `CFRetain`s the new pointer prior to setting it. No changes to tests since this makes no semantic changes. Issue: https://github.com/flutter/flutter/issues/137801 [C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style