[WK2 iOS] During momentum scroll, getBoundingClientRect returns wrong coordinates (missing images on pinterest, elle.com and many other sites)

[Simon Fraser (smfr)]

[WK2 iOS] During momentum scroll, getBoundingClientRect returns wrong coordinates (missing images on pinterest, elle.com and many other sites)

[Simon Fraser (smfr)]

Created attachment 314905 [details]
Patch

[Build Bot]

Comment on attachment 314905 [details]
Patch

Attachment 314905 [details] did not pass ios-sim-ews (ios-simulator-wk2):
Output: http://webkit-queues.webkit.org/results/4074919

New failing tests:
scrollingcoordinator/ios/sync-layer-positions-after-scroll.html

[Build Bot]

Created attachment 314912 [details]
Archive of layout-test-results from ews124 for ios-simulator-wk2

The attached test failures were seen while running run-webkit-tests on the ios-sim-ews.
Bot: ews124  Port: ios-simulator-wk2  Platform: Mac OS X 10.12.5

[Simon Fraser (smfr)]

Created attachment 315065 [details]
Patch

[Dean Jackson]

Comment on attachment 315065 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=315065&action=review

> Source/WebCore/ChangeLog:19
> +        but fix the scrolling tree logic to work correctly in this cause.

Typo: cause

> LayoutTests/fast/visual-viewport/ios/get-bounding-client-rect-unstable.html:49
> +            testRunner.runUIScript(simulateScrollingStart(500), function() {
> +                checkBoundingClientRect(-150);
> +
> +                debug('Finishing scroll');
> +                testRunner.runUIScript(simulateScrollingEnd(), function() {

Is it ok to call a UIScript from within a UIScript?

[Simon Fraser (smfr)]

rdar://problem/32864180

[Simon Fraser (smfr)]

https://trac.webkit.org/r219320