REGRESSION (iOS 16): sina.cn: Find on Page highlights obscure the text behind them

[pxlcoder]

ed56087

REGRESSION (iOS 16): sina.cn: Find on Page highlights obscure the text behind them
https://bugs.webkit.org/show_bug.cgi?id=251707
rdar://102302792

Reviewed by Wenson Hsieh.

sina.cn contains elements with "-webkit-user-select: none". Prior to iOS 16,
any text found within these elements would count towards the number of results,
but would not be highlighted.

Find-in-page logic was refactored in iOS 16 to support UIKit's new Find & Replace
API. As part of these changes, find-in-page began storing/restoring ranges, rather
than simply updating selection. Consequently, the `TextIndicator` used to draw
highlights is created from a `SimpleRange`, rather than the current selection.
The previously used constructor would early return if the selection was empty
(as is the case when attempting to select a "-webkit-user-select: none" element),
resulting the the pre-iOS 16 behavior described above.

`TextIndicator` does not know how to take snapshots of "-webkit-user-select: none"
content. Consequently, the highlight is painted without any text, leading to
found text getting obscured.

For now, restore the pre-iOS 16 behavior, and do not draw highlights if the
selection is empty. In the longer term, `TextIndicator` should be taught to
draw this content (tracked in webkit.org/b/251709). Note that following this
change, there is still a net progression over pre-iOS 16 behavior, where
WebKit will indicate found results with "-webkit-user-select: none" by drawing
"holes".

* Source/WebKit/WebProcess/WebPage/WebFoundTextRangeController.cpp:
(WebKit::WebFoundTextRangeController::drawRect):

Additionally, move the use of `GraphicsContext` closer to the painting logic to
avoid running unnecessary code.

Canonical link: https://commits.webkit.org/259857@main

99057c5

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🛠 gtk	✅ 🛠 wincairo
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 gtk-wk2
	✅ 🧪 api-ios	✅ 🧪 mac-wk1	✅ 🧪 api-gtk
	✅ 🛠 tv	❌ 🧪 mac-wk2
	✅ 🛠 tv-sim	✅ 🧪 mac-AS-debug-wk2
	✅ 🛠 watch	✅ 🧪 mac-wk2-stress
	✅ 🛠 watch-sim
✅ 🛠 🧪 unsafe-merge

[webkit-early-warning-system]

EWS run on current version of this PR (hash 99057c5)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🛠 gtk	✅ 🛠 wincairo
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 gtk-wk2
	✅ 🧪 api-ios	✅ 🧪 mac-wk1	✅ 🧪 api-gtk
	✅ 🛠 tv	❌ 🧪 mac-wk2
	✅ 🛠 tv-sim	✅ 🧪 mac-AS-debug-wk2
	✅ 🛠 watch	✅ 🧪 mac-wk2-stress
	✅ 🛠 watch-sim
✅ 🛠 🧪 unsafe-merge

[pxlcoder]

Thanks for the review!

[webkit-commit-queue]

Committed 259857@main (ed56087): https://commits.webkit.org/259857@main

Reviewed commits have been landed. Closing PR #9618 and removing active labels.