commit a687e1c3da8c5ff8968776d5b72d370d019dc552
author David Baron <dbaron@chromium.org> Mon Apr 14 23:02:39 2025
committer Chromium LUCI CQ <chromium-scoped@luci-project-accounts.iam.gserviceaccount.com> Mon Apr 14 23:02:39 2025
tree 10af7e96f9f2679d27952f8b554c94567ce8ee33
parent 00b63a3e5a3fa6b9992f456740e261366131f6ad

Make resizing relative to original position.

When resizing an element with the CSS resize property such as a
textarea, changing the size of the element might move the origin
(top-left corner) of the element.  This makes such changes not affect
what a resize gesture is relative to, by storing the transform at the
start of a resize.  This makes resizing of elements that are positioned
relative to the end-edge of the layout, or centered, etc. work better.
(The existing code worked properly for start-edge positioned elements in
both LTR and RTL.)  This operates on the principle that the desired size
change (visible, after transforms) is the amount of mouse movement, and
it's ok if that means the mouse is no longer tracking the position of
the resizer.

Prior to the change, these two added tests fail:
  external/wpt/css/css-ui/resize-textarea-relative-to-right-001.tentative.html
  external/wpt/css/css-ui/resize-textarea-rtl-002.tentative.html

Note that existing web tests test resizers with transforms:
  fast/css/resize-corner-tracking-transformed-iframe.html
  fast/css/resize-corner-tracking-transformed.html
  external/wpt/css/css-overflow/resizer-transform.tentative.html

Fixed: 40697767, 41236895
Change-Id: I31382aa84af4d4836fba54e8af4622213a320d3c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6441001
Commit-Queue: David Baron <dbaron@chromium.org>
Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1446823}