Bug 1745492 Part 2: Update MacIOSurface handling to deal with 10-bit formats. r=media-playback-reviewers,gfx-reviewers,lsalzman,alwu
Bug 1745492 Part 2: Update MacIOSurface handling to deal with 10-bit formats. r=media-playback-reviewers,gfx-reviewers,lsalzman,alwu

This fixes an issue caused by landing Bug 1679927. Now that it's possible to
get 10-bit formats in macOS, the texture pipeline has to be updated to pass
those surfaces to WebRender.

This also contains a drive-by comment on D3D11 handing of 10-bit WebRender
display items. It was not clear why specifing 16-bit color depth for P010
format was correct there, but should be specified as 10-bit color elsewhere.

This also contains another drive-by fix to comments in webrender describing
the RG16 enum.

Differential Revision: https://phabricator.services.mozilla.com/D136823

[ghsync] From https://hg.mozilla.org/mozilla-central/rev/823e45ca5fd34742d162b466ee884d5111e12abd

servo/webrender,servo/webrender,servo/webrender,servo/webrender,servo/webrender,servo/webrender