Bug 1656700 [wpt PR 24843] - Reland "Use border box or layout overflow rect for layou...
commitd17b7a63da346bd0c18e40cd4f1f8afda30d6207
authorXianzhu Wang <wangxianzhu@chromium.org>
Fri, 7 Aug 2020 12:41:34 +0000 (7 12:41 +0000)
committermoz-wptsync-bot <wptsync@mozilla.com>
Fri, 7 Aug 2020 23:25:58 +0000 (7 23:25 +0000)
tree4f94368a29d2e28d6c5b080c43164bf7b80d68b9
parent3245374ea978151f10323dcfc4e3a7699cb6711f
Bug 1656700 [wpt PR 24843] - Reland "Use border box or layout overflow rect for layout shift tracking", a=testonly

Automatic update from web-platform-tests
Reland "Use border box or layout overflow rect for layout shift tracking"

This reverts commit 491b5a9cbe75eb9cdde6e9e0b21e8246f441b086.

The original CL was reverted because it caused failure on MSAN bots
due to use of uninitialized value.

The reason was that PaintInvalidatorContext::tree_builder_context_
pointed into an PrePaintTreeWalkContext entry in a vector, and the
vector could be reallocated when we added new entries, causing the
pointer in the parent PaintInvalidatorContext to point to an invalid
address.

Now remove PaintInvalidatorContext::tree_builder_context_ and add
PaintInvalidatorContext::transform_ (which was the only used information
from the parent PaintInvalidatorContext) to avoid the problem.

Original change's description:
> Revert "Use border box or layout overflow rect for layout shift tracking"
>
> This reverts commit 0933392f84b4bb96466bd86c0e814d96f63ba137.
>
> Reason for revert: ASAN/MSAN failures due to "use of uninitialized value"; see e.g. https://logs.chromium.org/logs/chromium/buildbucket/cr-buildbucket.appspot.com/8873209606965810848/+/steps/browser_tests/0/logs/Deterministic_failure:_AllForms__x2f_FormStructureBrowserTest.DataDrivenHeuristics__x2f_148__status_FAILURE_/0
>
> Original change's description:
> > Use border box or layout overflow rect for layout shift tracking
> >
> > This CL addresses the following issues of layout shift tracking:
> > - Changed visual overflows triggered layout shift report
> >   (originally filed as crbug.com/1090763).
> > - Descendant layout overflows were not included in ancestor's layout
> >   shift report.
> > - Unnecessary descendant layout shift report.
> > - Slow visual rect calculation for LayoutInline and LayoutText.
> >
> > It includes the following changes
> > - Track LayoutBoxes and LayoutTexts only.
> > - Track both old and new starting points and visual representations
> >   instead of using location of visual rects as starting points.
> > - For a LayoutBox, the local visual representation is the layout
> >   overflow rect if the LayoutBox has layout overflow and doesn't clip
> >   overflow. Otherwise use the border box rect.
> > - For a LayoutText, suppose its shift causes shift of all contents
> >   in containing block logically below the LayoutText, and use that
> >   part of visual representation of the containing block as the visual
> >   representation of the shift.
> > - Map both local starting points and local visual representations to
> >   the initial containing block and viewport.
> >
> > This has the following benefits:
> > - More accurate starting points and visual representations, conforming
> >   to the specs;
> > - Better performance by
> >   * avoiding unnecessary layout shift reports of descendants
> >   * avoiding slow LayoutInline and LayoutText visual rect calculation.
> > - sizeof(LayoutObject) is reduced by 16 bytes because now we use the
> >   previous geometry data in LayoutBoxes for paint invalidation.
> >
> > Bug: 1108622
> > Change-Id: I7ebb4e250e7ca2a03b4dadea50034e300e55ad84
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2319538
> > Reviewed-by: Steve Kobes <skobes@chromium.org>
> > Reviewed-by: Koji Ishii <kojii@chromium.org>
> > Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#793806}
>
> TBR=wangxianzhu@chromium.org,skobes@chromium.org,kojii@chromium.org
>
> Change-Id: I590f2abc4a48ba65bdfe7a948ffce00b299f9e06
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: 1108622
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2333578
> Reviewed-by: Peter Kasting <pkasting@chromium.org>
> Commit-Queue: Peter Kasting <pkasting@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#793874}

# Not skipping CQ checks because this is a reland.

Bug: 1108622
Change-Id: I253a24799b6d2a3af346d4f65e3889217064b035
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2333648
Reviewed-by: Philip Rogers <pdr@chromium.org>
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#794218}

--

wpt-commits: 5111694f4f8d0ae21d4535e53f208d24061411a5
wpt-pr: 24843
testing/web-platform/tests/layout-instability/inline-flow-shift-vertical-rl.html [new file with mode: 0644]
testing/web-platform/tests/layout-instability/inline-flow-shift.html [new file with mode: 0644]
testing/web-platform/tests/layout-instability/outline.html [new file with mode: 0644]