After some discussions the CSS WG agreed that stretch should not only
grow items, but also stretch them to fit its grid area.
That way the "min-width|height: auto" is somehow ignored for grid items.
More info at: w3c/csswg-drafts#283
The good part is that this allows us to remove some ugly code we've
in LayoutBox that was only used by Grid Layout.
The tests have been updated according to the new expected behavior.
For images, we'll be stretching on both axis right nos, so the aspect
ratio won't be preserved. The default behavior might change in those
cases, but that should be implemented in a different patch.
This patch imports the CSS Grid Layout test suite from csswg-test repository.
Currently we're passing most of the but:
* grid-layout-properties.html: An old known bug (crbug.com/511177).
* grid-support-grid-template-areas-001.xht &
grid-inline-support-grid-template-areas-001.xht: Because of an issue
with testharness.js (crbug.com/687492).
Additionally I'm skipping the tests related to "Implied Minimum Size
of Grid Items" (https://drafts.csswg.org/css-grid/#min-size-auto),
because the test suite needs to be updated after the CSS WG resolves
the following issue: w3c/csswg-drafts#283
See crbug.com/666940 for more details.