Avoid reattachWhitespaceSiblings when renderer does not change.

Avoid reattachWhitespaceSiblings when renderer does not change.

If the renderer is null before and after the style recalc, there is no need
to reattach whitespace siblings. It is necessary to check for needsAttach()
since the old renderer might have been detached by lazyReattachIfAttached(),
for instance.

BUG=340213
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=168668

[leviw_travelin_and_unemployed, 2014-03-06 18:29:04]

LGTM. Great!

[leviw_travelin_and_unemployed, 2014-03-06 18:29:10]

The CQ bit was checked by leviw@chromium.org

[commit-bot: I haz the power, 2014-03-06 18:29:18]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/rune@opera.com/188543002/1

[commit-bot: I haz the power, 2014-03-06 18:50:09]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-03-06 18:50:10]

Try jobs failed on following builders: linux_blink

[leviw_travelin_and_unemployed, 2014-03-06 18:52:14]

The CQ bit was checked by leviw@chromium.org

[commit-bot: I haz the power, 2014-03-06 18:52:22]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/rune@opera.com/188543002/1

[commit-bot: I haz the power, 2014-03-06 19:03:32]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/rune@opera.com/188543002/1

[commit-bot: I haz the power, 2014-03-06 19:33:52]

Change committed as 168668

[esprehn, 2014-03-06 19:40:24]

https://codereview.chromium.org/188543002/diff/1/Source/core/dom/Element.cpp
File Source/core/dom/Element.cpp (right):

https://codereview.chromium.org/188543002/diff/1/Source/core/dom/Element.cpp#...
Source/core/dom/Element.cpp:1601: if (rendererWillChange || renderer())
You're going to reattach on the initial attach of an element which is display:
none too which isn't right.

if !renderer() && needsAttach() before and then !renderer() after as well we
don't need need to reattach whitespace.

[rune, 2014-03-06 20:56:33]

https://codereview.chromium.org/188543002/diff/1/Source/core/dom/Element.cpp
File Source/core/dom/Element.cpp (right):

https://codereview.chromium.org/188543002/diff/1/Source/core/dom/Element.cpp#...
Source/core/dom/Element.cpp:1601: if (rendererWillChange || renderer())
On 2014/03/06 19:40:24, esprehn wrote:
> You're going to reattach on the initial attach of an element which is display:
> none too which isn't right.
> 
> if !renderer() && needsAttach() before and then !renderer() after as well we
> don't need need to reattach whitespace.

The problem is that !renderer() && needsAttach() also happens when
lazyReattachIfAttached() has been called. For that case, there are possibly
whitespace renderer garbage lying around after detach() has been called from
lazyReattachIfAttached(). At this point, I don't know if that's the case or not.
This case is hit in two of the layout tests.