Bug 1526746 [wpt PR 15284] - [css-grid] Overflow should be computed w…

…ith the actual logical bottom, a=testonly

Automatic update from web-platform-tests
[css-grid] Overflow should be computed with the actual logical bottom

In order to compute the 'auto' height of the grid container, we set
temporarily a value based on the tracks' size. We can see this value as
a kind of 'intrinsic height'. Then, we call to the UpdateLogicalHeight
function to finally compute the grid container's actual logical height.

In order to compute the overflow area in the grid container we should
use the result of the ClientLogicalBottom function. However, we were
retrieving this value just after setting the tracks-based temporary
height, and before computing the actual logical height.

The consequence of this wrong logic is that empty grid areas may
affect the result of the ClientLogicalBottom and, as it's described
in the bug, conclude that there is a content overflow in the grid
container, even if such container has no grid items at all.

Since the grid itself is not a box, it can't contribute to the grid
container's content size; instead, its grid items should.

This change ensures that we always use the actual grid container's
logical bottom to properly compute the overflow area.

Bug: 928885
Change-Id: I05f86fbce06a83c0dbc0d5389bf0416763f8588a
Reviewed-on: https://chromium-review.googlesource.com/c/1459620
Commit-Queue: Javier Fernandez <jfernandezigalia.com>
Reviewed-by: Manuel Rego <regoigalia.com>
Cr-Commit-Position: refs/heads/master{#630735}

--

wpt-commits: aa6f52fc7b99559377c760a550e842438efa91a1
wpt-pr: 15284

UltraBlame original commit: 4b473920911b430bb46c02f770179d10f61649b4

testing/web-platform/tests/css/css-grid/grid-model/grid-areas-overflowing-grid-container-001.html

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