Bug 284491 – AX: When Safari is full-screen, AXIsolatedObject::screenRelativePosition() hits the main-thread unnecessarily

• Status: RESOLVED
• Resolution: FIXED
• Component: Accessibility

[Tyler Wilcock]

This happens because after https://bugs.webkit.org/show_bug.cgi?id=267957, AXIsolatedObject::screenRelativePosition() uses the cached root screen relative position to compute the screen relative position for every other object. But because we intentionally don't cache properties that are in their default-value state, we wouldn't cache AXPropertyName::ScreenRelativePosition {0, 0} for the root (which is the right value when Safari is full-screen). Thus, this:

if (auto rootPoint = rootNode->optionalAttributeValue<FloatPoint>(AXPropertyName::ScreenRelativePosition))

Fails to evaluate to true, and we hit the main-thread.

[Radar WebKit Bug Importer]

<rdar://problem/141314514>

[Tyler Wilcock]

Pull request: https://github.com/WebKit/WebKit/pull/37818

[EWS]

Committed 287754@main (969b96235a07): <https://commits.webkit.org/287754@main>

Reviewed commits have been landed. Closing PR #37818 and removing active labels.