[webkit-reviews] review denied: [Bug 113137] Test if non-immediate descendants obscure background : [Attachment 194767] elements with filters may be transparent

[bugzilla-daemon at webkit.org]

Simon Fraser (smfr) <simon.fraser at apple.com> has denied Antti Koivisto
<koivisto at iki.fi>'s request for review:
Bug 113137: Test if non-immediate descendants obscure background
https://bugs.webkit.org/show_bug.cgi?id=113137

Attachment 194767: elements with filters may be transparent
https://bugs.webkit.org/attachment.cgi?id=194767&action=review

------- Additional Comments from Simon Fraser (smfr) <simon.fraser at apple.com>
View in context: https://bugs.webkit.org/attachment.cgi?id=194767&action=review


> Source/WebCore/rendering/RenderBox.cpp:1220
> +	   if (childLayer->zIndex() < 0)
> +	       return false;

It's hard to me to know whether this test is reliable, without an explicit
check for the childBox's stacking context being some specific ancestor. For
example, what happens if the renderer we're checking for opaqueness is A here:

<div style="postion: absolute; z-index: 0"> <!-- stacking context -->
  <div style="postion: absolute; z-index: -2"> <!-- A -->
    <div style="postion: absolute; z-index: -1"></div>
  </div>
</div>