We fail this WPT test:
https://wpt.fyi/results/css/css-grid/alignment/grid-content-alignment-second-pass-002.html

At least for the first subtest, the issue is that we're not honoring the percent-sized grid-template-rows value (expressed in the grid shorthand). Reduced testcase attached.

The percent size here is a bit tricky, since there's no explicit height on the container for the percent value to resolve against. It seems we need to do a second percent-resolving pass (as hinted by the name of the WPT test) after we've resolved an initial measurement for the height of the grid container.

STR with reduced testcase:

1. Load attached testcase.

EXPECTED RESULTS:
Mostly-lime rectangle with small strip of orange at the top.

ACTUAL RESULTS:
Fully orange rectangle, no lime visible.