[webkit-changes] [WebKit/WebKit] 8c21d1: Invalid layer contents when navigating and hoverin...

[mattwoodrow]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: 8c21d17d0a028e2002f8361b0b93c02785473dcb
      https://github.com/WebKit/WebKit/commit/8c21d17d0a028e2002f8361b0b93c02785473dcb
  Author: Matt Woodrow <mattwoodrow at apple.com>
  Date:   2023-12-11 (Mon, 11 Dec 2023)

  Changed paths:
    M Source/WebKit/GPUProcess/graphics/RemoteImageBufferSet.cpp

  Log Message:
  -----------
  Invalid layer contents when navigating and hovering on slack and Facebook.
https://bugs.webkit.org/show_bug.cgi?id=266255
<rdar://119505126>

Reviewed by Mike Wyrzykowski.

Sometimes when hovering text entries on slack, the previous highlight isn't fully removed.
Likewise, navigating between the profile page and home page on Facebook can leave remnants
of the rendering of the previous page.

The code is resetting the graphics context clip to remove any partial-update clips applied
from a previous draw into that context. Unfortunately this was happening after the copy
forward draw, not before. This moves it up, so that we're not clipped to the old draw region.

It would be nice to add a test here.

* Source/WebKit/GPUProcess/graphics/RemoteImageBufferSet.cpp:
(WebKit::RemoteImageBufferSet::prepareBufferForDisplay):

Canonical link: https://commits.webkit.org/271908@main