[webkit-changes] [WebKit/WebKit] fdd372: Scrolling with page granularity using keyboard smo...

[Richard Robinson]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: fdd3720bd643eda26832e2155f1f939f08cd040a
      https://github.com/WebKit/WebKit/commit/fdd3720bd643eda26832e2155f1f939f08cd040a
  Author: Richard Robinson <richard_robinson2 at apple.com>
  Date:   2022-09-28 (Wed, 28 Sep 2022)

  Changed paths:
    M Source/WebCore/platform/KeyboardScrollingAnimator.cpp
    M Source/WebCore/platform/ScrollableArea.h
    M Source/WebKit/UIProcess/ios/WKKeyboardScrollingAnimator.mm

  Log Message:
  -----------
  Scrolling with page granularity using keyboard smooth scrolling doesn't account for fixed content
https://bugs.webkit.org/show_bug.cgi?id=245746
rdar://100469555

Reviewed by Tim Horton.

When keyboard smooth scrolling is enabled, `KeyboardScrollingAnimator::scrollDistance`
is used, which is analagous to `ScrollableArea::scroll`. However, while the
latter accounts for page's having fixed content when scrolling with page
granularity, the former never does.

This PR fixes this by including the same logic that `ScrollableArea::scroll` has
to adjust the scroll step into `KeyboardScrollingAnimator::scrollDistance`.

* LayoutTests/scrollbars/scrolling-backward-by-page-accounting-bottom-fixed-elements-on-keyboard-spacebar.html:
* Source/WebCore/platform/KeyboardScrollingAnimator.cpp:
(WebCore::KeyboardScrollingAnimator::scrollDistance const):
* Source/WebCore/platform/ScrollableArea.h:

Canonical link: https://commits.webkit.org/254963@main