[webkit-changes] [WebKit/WebKit] ed2bfb: AX: Update cached text runs when line layout changes

[Joshua Hoffman]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: ed2bfb346eb51503269ee148064da49d3e8d5da9
      https://github.com/WebKit/WebKit/commit/ed2bfb346eb51503269ee148064da49d3e8d5da9
  Author: Joshua Hoffman <jhoffman23 at apple.com>
  Date:   2024-02-19 (Mon, 19 Feb 2024)

  Changed paths:
    A LayoutTests/accessibility/ax-thread-text-apis/dynamic-text-line-wrapping-expected.txt
    A LayoutTests/accessibility/ax-thread-text-apis/dynamic-text-line-wrapping.html
    M Source/WebCore/accessibility/AXLogger.cpp
    M Source/WebCore/accessibility/AXObjectCache.cpp
    M Source/WebCore/accessibility/AXObjectCache.h
    M Source/WebCore/accessibility/isolatedtree/AXIsolatedTree.cpp
    M Source/WebCore/rendering/RenderBlockFlow.cpp

  Log Message:
  -----------
  AX: Update cached text runs when line layout changes
https://bugs.webkit.org/show_bug.cgi?id=269628
rdar://problem/123122761

Reviewed by Tyler Wilcock.

When AX_THREAD_TEXT_APIS is enabled, we cache textruns when objects are initialized. But, when their line layout
updates (for example, when the width of their container changes), we do not update the text runs, meaning they
will become stale and the line APIs will return incorrect information to clients.

This patch hooks into line layout, and updates the cached runs for objects that have changed.

One consideration while exploring this patch was whether we need to debounce this caching. But, sampling shows
that this computation is not that expensive, making debouncing excessive.

* LayoutTests/accessibility/ax-thread-text-apis/dynamic-text-line-wrapping-expected.txt: Added.
* LayoutTests/accessibility/ax-thread-text-apis/dynamic-text-line-wrapping.html: Added.
* Source/WebCore/accessibility/AXLogger.cpp:
(WebCore::operator<<):
* Source/WebCore/accessibility/AXObjectCache.cpp:
(WebCore::AXObjectCache::onTextRunsChanged):
(WebCore::AXObjectCache::updateIsolatedTree):
* Source/WebCore/accessibility/AXObjectCache.h:
* Source/WebCore/accessibility/isolatedtree/AXIsolatedTree.cpp:
(WebCore::AXIsolatedTree::updateNodeProperties):
* Source/WebCore/rendering/RenderBlockFlow.cpp:
(WebCore::RenderBlockFlow::layoutModernLines):

Canonical link: https://commits.webkit.org/274999@main



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