Implementation of the new `WebGLRenderingContext` attribute `drawingBufferColorSpace`. https://registry.khronos.org/webgl/specs/latest/1.0/#5.14.1 This is currently restricted to macOS, and the two acceptable `PredefinedColorSpace` values are `"srgb"` and `"display-p3"`.
<rdar://problem/101663516>
Pull request: https://github.com/WebKit/WebKit/pull/5613
Committed 256208@main (0dfb608af54f): <https://commits.webkit.org/256208@main> Reviewed commits have been landed. Closing PR #5613 and removing active labels.