These operations should still apply even if they are off screen, because
they affect painting of things outside of their bounding rectangles.
This commit makes us always apply these, regardless of if they are in
the visible region. However, if they are outside that region, we
replace them with simple clip-rect commands, which have the same
effect (not painting anything) but are cheaper than computing a full
mask bitmap.
This also adds support for `xyz` as it defaults to `xyz-d65`. We now
pass the following WPT tests:
- css/css-color/xyz-001.html
- css/css-color/xyz-002.html
- css/css-color/xyz-004.html
- css/css-color/xyz-d65-001.html
- css/css-color/xyz-d65-002.html
- css/css-color/xyz-d65-004.html
A few are skipped for now:
- A few ref tests fail
- Crash tests are not supported by our runner and time out
- top-level-is-scope.html crashes and needs further investigation