To properly compute (the video) element's content size for
layout requires to dirty the element on any intrinstic size changes.
Full list of the operations which cause layout invalidation:
- media metadata update (NEW)
- removing "src" attribute
- video frame update
- show poster image
Testing:
html/semantics/embedded-content/the-video-element/intrinsic_sizes.htm
Fixes: https://github.com/servo/servo/issues/34434
Signed-off-by: Andrei Volykhin <andrei.volykhin@gmail.com>