tree 50f518fcd47f84db734099a789e09b35f4c4745a
parent 50654f1d617a8d267c3eecc66ffd9f0d04811da0
author Sahir Vellani <sahir.vellani@microsoft.com> 1584486107 -0700
committer Blink WPT Bot <blink-w3c-test-autoroller@chromium.org> 1584487354 -0700

Resize Observer: Observe Device Pixel Content Box

In order to correctly snap box sizes to pixels using SnapSizeToPixel,
the function FragmentData::PaintOffset() needs to be used. This function
provides an accurate location/offset of the box in question. However,
this the paint offset is determined in the PrePaint lifecycle phase. To
accommodate this, LocalFrameView::NotifyResizeObservers is moved to
LocalFrameView::UpdateLifecyclePhasesInternal. In addition,
UpdateLifecyclePhasesInternal is refactored so that all lifecycle
steps prior to paint are run in a loop. The loop is broken when one of
the following 3 conditions are met:

1) the target state < kPaintClean
2) No changes to layout are pending
3) Resize observer loop limit is reached

Resize Observer can now observe changes to the device pixel content box.
ResizeObserverEntry now reports the dimensions of the pixel snapped
content box.

Bug: 1055579
Change-Id: Ibc7b2e4e0a8468f9af74c8cfaadd02e4f0bcfc1f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2071575
Reviewed-by: Philip Rogers <pdr@chromium.org>
Reviewed-by: Daniel Libby <dlibby@microsoft.com>
Reviewed-by: Stefan Zager <szager@chromium.org>
Commit-Queue: Sahir Vellani <sahir.vellani@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#751159}