[webkit-changes] [WebKit/WebKit] a7fd0d: [iOS] Adopt `-[UIScrollView setTransfers(Horizonta...

[Wenson Hsieh]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: a7fd0d9da2784c15f4d9afa9b91c812ebdebce49
      https://github.com/WebKit/WebKit/commit/a7fd0d9da2784c15f4d9afa9b91c812ebdebce49
  Author: Wenson Hsieh <wenson_hsieh at apple.com>
  Date:   2023-10-27 (Fri, 27 Oct 2023)

  Changed paths:
    M Source/WTF/wtf/PlatformHave.h
    M Source/WebKit/UIProcess/RemoteLayerTree/ios/ScrollingTreeScrollingNodeDelegateIOS.mm
    M Source/WebKit/UIProcess/ios/UIKitUtilities.h
    M Source/WebKit/UIProcess/ios/UIKitUtilities.mm

  Log Message:
  -----------
  [iOS] Adopt `-[UIScrollView setTransfers(Horizontal|Vertical)ScrollingToParent:]`
https://bugs.webkit.org/show_bug.cgi?id=263755
rdar://114330057

Reviewed by Richard Robinson.

Adopt equivalent replacement APIs, corresponding to these two `UIScrollView` SPI methods:
• `-_setAllowsParentToBeginHorizontally:`   -> `-setTransfersHorizontalScrollingToParent`
• `-_setAllowsParentToBeginVertically:`     -> `-setTransfersVerticalScrollingToParent`

To make this work while maintaining compatibility with iOS 17 and prior, we add a new compile-time
flag along with a runtime selector check, and only use this new API when both checks pass.

* Source/WTF/wtf/PlatformHave.h:

Remove a compile-time flag that's no longer needed.

* Source/WebKit/UIProcess/RemoteLayerTree/ios/ScrollingTreeScrollingNodeDelegateIOS.mm:
(WebKit::ScrollingTreeScrollingNodeDelegateIOS::updateScrollViewForOverscrollBehavior):
* Source/WebKit/UIProcess/ios/UIKitUtilities.h:
* Source/WebKit/UIProcess/ios/UIKitUtilities.mm:
(-[UIScrollView _wk_setTransfersHorizontalScrollingToParent:]):
(-[UIScrollView _wk_setTransfersVerticalScrollingToParent:]):

Add new helper category methods on `UIScrollView` to abstract away the fallback logic described
above.

Canonical link: https://commits.webkit.org/269850@main