Scrollbar width is not applied when element hidden

Scrollbar width is not applied when element hidden

Webkit has css properties through which custom scroll bars can be added.
In case the element's visibility property is hidden and custom scrollbar 
properties are applied the scrollbar width is not considered when querying
the element.clientWidth. In case of non-custom scrollbars whether the
element's visibility property is hidden or not correct scrollbar width is
considered.

When a custom scrollbar is created there is a check whether the renderer to
which scrollbar is added is visible or not. This check is not required since
for non-custom scrollbars the same check is not present. Also whether the
element's visibility property is hidden or not a placeholder is set for the
element.

Both behavior i.e custom and non-custom scrollbars should be same.

I already landed this patch on Webkit. Just modified the layout test file.
http://trac.webkit.org/changeset/155323

R=esprehn@chromium.org,eseidel@chromium.org
BUG=343521
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=175123

[Gurpreet, 2014-02-19 09:33:46]

Please review. Thanks.

[eseidel, 2014-03-10 18:12:11]

I don't really understand what this is changing.  It looks like it's causing
custom scrollbars to still create renderers even when they're visibility:
hidden... which seems reasonable given that visibility: hidden objects normally
create renderers.

[Gurpreet, 2014-03-11 05:03:07]

On 2014/03/10 18:12:11, eseidel wrote:
> I don't really understand what this is changing.  It looks like it's causing
> custom scrollbars to still create renderers even when they're visibility:
> hidden... which seems reasonable given that visibility: hidden objects
normally
> create renderers.

The clientWidth was not giving the same value for element having custom scroll
bars
and the element is hidden and visible as compared to clientWidth of element
having 
non-custom scrollbars when element is hidden and visible. So made changes for
the 
functionality to be same.

[Gurpreet, 2014-03-18 13:06:15]

Hi Eric. Please review. Thanks.

[Gurpreet, 2014-03-24 12:12:24]

Hi Eric. Can you please review this? Thanks.

[Gurpreet, 2014-04-01 14:41:11]

Hi Eric. Can you please review this? Thanks.

[Gurpreet, 2014-05-05 09:40:45]

Hi Can someone please review this. Thanks.

[eseidel, 2014-05-29 00:27:52]

Julien is the right reviewer for scrollbar changes.

Sorry for the long delay!

Please track jchaffraix down in #blink if you don't get a quick review.

[eseidel, 2014-05-29 00:28:49]

In any case, this looks right. rslgtm.

Presumably you tested in FF or IE?

[leviw_travelin_and_unemployed, 2014-05-29 00:43:23]

On 2014/05/29 00:28:49, eseidel wrote:
> In any case, this looks right. rslgtm.
> 
> Presumably you tested in FF or IE?

Seems okay to me, too. LGTM.

[Gurpreet, 2014-05-29 05:54:34]

The CQ bit was checked by k.gurpreet@samsung.com

[commit-bot: I haz the power, 2014-05-29 05:54:48]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/k.gurpreet@samsung.com/163383002/50001

[commit-bot: I haz the power, 2014-05-29 07:13:51]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  linux_blink_dbg on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/linux_blink_dbg/builds/1...)
  linux_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/linux_blink_rel/builds/9911)

[Gurpreet, 2014-05-30 08:21:31]

The CQ bit was unchecked by k.gurpreet@samsung.com

[Gurpreet, 2014-05-30 08:21:35]

The CQ bit was checked by k.gurpreet@samsung.com

[commit-bot: I haz the power, 2014-05-30 08:22:00]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/k.gurpreet@samsung.com/163383002/50001

[commit-bot: I haz the power, 2014-05-30 09:12:53]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  win_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/win_blink_rel/builds/9891)

[commit-bot: I haz the power, 2014-05-30 10:33:21]

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

[commit-bot: I haz the power, 2014-05-30 10:33:21]

Try jobs failed on following builders:
  win_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/win_blink_rel/builds/9900)

[Gurpreet, 2014-05-30 10:41:59]

The CQ bit was unchecked by k.gurpreet@samsung.com

[Gurpreet, 2014-05-30 11:00:00]

The CQ bit was checked by k.gurpreet@samsung.com

[commit-bot: I haz the power, 2014-05-30 11:00:25]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/k.gurpreet@samsung.com/163383002/50001

[commit-bot: I haz the power, 2014-05-30 13:09:13]

Change committed as 175123