tree cdd6cac5b517eae8f866d05ba6b2d18942ccfb80
parent 427391a1ab274ac1ec1a60a9f41c8fa8ed12169d
author wenson_hsieh@apple.com <wenson_hsieh@apple.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc> 1557896276 +0000
committer wenson_hsieh@apple.com <wenson_hsieh@apple.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc> 1557896276 +0000

Missing cursor/caret showing in search field on google.com
https://bugs.webkit.org/show_bug.cgi?id=197862
<rdar://problem/50291989>

Reviewed by Simon Fraser.

Source/WebCore:

In this bug, the search field is inside of a fixed position container, which is inside of an empty "overflow:
hidden" form element (the new layout test demonstrates a simple version of this). The layer of the fixed
position container's renderer has an overflow clipping layer of itself, and its clipping rect is non-empty, so
the heuristic initially identifies the layer as not fully clipped. However, as the heuristic ascends the
RenderLayer tree, it then finds the layer for the "overflow: hidden" form element's renderer; this layer is
completely clipped, which causes the heuristic to incorrectly believe that the editable element is completely
clipped.

To fix the bug, this patch reworks the clipping portion of the heuristic, such that we no longer need to ascend
the layer tree. Instead of computing the clip rect relative to the nearest ancestor that has an overflow clip
and then walking up the layer tree repeating this process, simply compute the clip rect relative to RenderView's
layer, and then walk up to the parent frame and repeat if necessary.

Test: editing/selection/ios/do-not-hide-selection-in-visible-field.html

* rendering/RenderLayer.cpp:
(WebCore::RenderLayer::isTransparentOrFullyClippedRespectingParentFrames const):

LayoutTests:

Add a new layout test that represents a reduced test case version of google.com's search field.

* editing/selection/ios/do-not-hide-selection-in-visible-field.html: Added.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@245317 268f45cc-cd09-0410-ab3c-d52691b4dbfc