-webkit-line-clamp is not respected when visibility is hidden

[Rob Brackett]

Created attachment 66913 [details]
Test case for -webkit-line-clamp and visibility hidden issue

When an element with visibility: hidden and -webkit-line-clamp: [anything] is appended to the DOM, the line clamp is not respected, even after setting visibility: visible or removing the visibility setting altogether. Note that the problem really seems to be that -webkit-line-clamp is ignored when rendering an element with visibility: hidden, not when making it visible (although the problem continues to persist then).

Test case attached.

Brief example:
  <div id="root">
    <div id="container">
      <p id="clamped">
        Blah blah blah
      </p>
    </div>
  </div>

1. Remove #container
2. Set visibility: hidden on #container
3. Append #container to #root
4. Remove visibility: hidden on #container

This also works if the element you remove and set visibility on is #clamped instead of #container. Just wanted to illustrate that it could be any node up the tree.

I can confirm the existence of this bug in Chrome Version 28.0.1500.71.

[Dima Voytenko]

Definitely seeing it on  39.0.2171.95: both desktop and mobile

[Sam Sneddon [:gsnedders]]

*** Bug 207013 has been marked as a duplicate of this bug. ***

[Brent Fulgham]

This appears to be tracked by this radar:
<rdar://59041496>