commit d3310fd73cb61bf1923db4c0f6521bed59b67fc8
author Xianzhu Wang <wangxianzhu@chromium.org> Sat Jul 20 01:21:33 2024
committer Chromium LUCI CQ <chromium-scoped@luci-project-accounts.iam.gserviceaccount.com> Sat Jul 20 01:21:33 2024
tree 3646799baed9a58156de29738a2c2c16e78c9bf8
parent 6f127747c0b4c9dc49a02a4e487a2122c963dbc0

Apply some fluent scrollbar optimizations to aura scrollbars

Thanks gastonr@microsoft.com for optimizing fluent scrollbars with
solid color thumbs and nine-patch track and buttons. This CL applies
these optimizations to aura to reduce resource usage for large
scrollbars and improve performance by reducing pixels to rasterize
in the main thread.

- Solid color thumb: Behind killswitch
  AuraScrollbarUsesSolidColorThumb, non-overlay aura scrollbar uses
  solid color quad for the thumb instead of rasterizing the thumb into
  a resource on the main thread. Previously the resource was just a
  bitmap containing the solid color, which was a waste of memory.

- Nine-patch track and buttons: Behind killswitch
  AuraScrollbarUsesNinePatchTrack, non-overlay aura scrollbar uses
  nine-patch resource for the track and buttons to reduce resource
  usage. During AppendQuads(), the resource will be split into 9
  quads, and the middle quads will be scaled to make the 9 quads
  reproduce the drawing of the whole scrollbar.

Bug: 40100995
Change-Id: I17b88eb8a6d94ea612e24d74b10c5d6bcc77ebbc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5699185
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Reviewed-by: Philip Rogers <pdr@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1330624}