Now that DOM/Flow traversals have been refactored out, the `recalc_style_for_subtree`
function in `css/matching.rs` can be removed, in lieu of just running the standard
`recalc_style_for_node` and `construct_flows` traversals sequentially. Now we
no longer have the maintenance headache of duplicating selector matching logic
in two places! \o/
This passes reftests with both default arguments, and with `-y 1`.
r? @pcwalton
Source-Repo: https://github.com/servo/servo
Source-Revision: 7eaeaeeb217e7cbd083fe318863e7de4b9f38e2b
