Properly implement text-align-last in legacy layout engine and IFC

[tuankiet65]

5c455ef

Properly implement text-align-last in legacy layout engine and IFC
https://bugs.webkit.org/show_bug.cgi?id=241050

Patch by Kiet Ho <tho22@apple.com > on 2022-06-03
Reviewed by Alan Bujtas.

The alignment of the last line in a block always follows the alignment specified
by text-align-last. However, the legacy layout engine currently follows the old
spec, where text-align-last only takes effect when text-align was 'justify' (see [1]
where this was changed), and IFC does not honor text-align-last at all. Fix both the
legacy layout engine and IFC to align the last line according to text-align-last.

Manually tested by running run-webkit-tests with IFC enabled and disabled.

[1]: w3c/csswg-drafts@c1f7023

* LayoutTests/TestExpectations:
* LayoutTests/fast/css3-text/css3-text-align-last/text-align-last-with-text-align-non-justify-expected.html: Removed.
* LayoutTests/fast/css3-text/css3-text-align-last/text-align-last-with-text-align-non-justify.html:
Remove obsolete test that tests the old behavior of text-align-line.
* Source/WebCore/layout/formattingContexts/inline/InlineLineBoxBuilder.cpp:
(WebCore::Layout::horizontalAlignmentOffset):
(WebCore::Layout::LineBoxBuilder::build):
* Source/WebCore/rendering/LegacyLineLayout.cpp:
(WebCore::LegacyLineLayout::textAlignmentForLine const):

Canonical link: https://commits.webkit.org/251294@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@295239 268f45cc-cd09-0410-ab3c-d52691b4dbfc

[nt1m]

@tuankiet65 This needs rebasing (should be straightforward). More importantly some tests are failing. fast/css3-text/css3-text-justify/text-justify-last-line-simple-line-layout.html suggests that the result is inconsistent with/without IFC enabled. Not sure about the repaint ones.

[webkit-early-warning-system]

Committed r295239 (251294@main): https://commits.webkit.org/251294@main

Reviewed commits have been landed. Closing PR #1169 and removing active labels.