Fall back to main thread if scroll hit test is affected by rounded corners #45797
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We had two issues:
for rounded corner clips, and the mask layer made the scroll begin
unreliable and fall back to the main thread. With fast rounded corners,
the scrolls were treated as reliable without checking if the point is
in or out of the rounded corners.
ancestor), as we only create InnerBorderRadiusClip for the contents,
the compositor doesn't actually know which part of the layer bounds
is transparent to hit test (e.g. if the scroller has a border which
is outside of the InnerBorderRadiusClip). Now with HitTestOpaqueness,
such layers have HitTestOpaqueness::kMixed.
This CL changes the behavior of
LayerTreeImpl::FindLayersUpToFirstOpaqueToHitTest (renamed from
FindLayerUpToFirstScrollableOrOpaqueToHitTest):
layer is affected by any fast rounded corners;
OpaqueToHitTest() (without checking IsScrollerOrScrollbar())
because a hit test on a scrollable layer is reliable only if it's
opaque to hit test.
Bug: 40277896
Change-Id: I1acb16f2c6790760661e8239ea1599035f83ea51
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5466909
Commit-Queue: Xianzhu Wang <[email protected]>
Reviewed-by: Steve Kobes <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1291538}