[Layout API] Start converting ScrollAnchor to new layout API

[Layout API] Start converting ScrollAnchor to new layout API

There were several references to a static method, scrollerLayoutBox,
which returns a raw LayoutBox*, which is deprecated by the new layout API.
I can't convert all the references at once because there is a long chain
of reference passing to unwind, so I (TEMPORARILY) duplicated the method
to create scrollerLayoutBoxItem() and started converting the easy
references to use that instead.

There are no functional changes.

BUG=499321
Committed: https://crrev.com/a313736960ccd0293046b192a3ea41aa4d2ae78f
Cr-Commit-Position: refs/heads/master@{#391522}

[pilgrim_google, 2016-05-04 14:34:41]

pilgrim@chromium.org changed reviewers:
+ eae@chromium.org, jsbell@chromium.org, leviw@chromium.org

[eae, 2016-05-04 14:37:31]

eae@chromium.org changed reviewers:
+ skobes@chromium.org

[eae, 2016-05-04 14:37:31]

+skobes so that he's aware of the effort

LGTM

[pilgrim_google, 2016-05-04 14:53:13]

The CQ bit was checked by pilgrim@chromium.org

[commit-bot: I haz the power, 2016-05-04 14:53:27]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1945353002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1945353002/1

[skobes, 2016-05-04 15:50:39]

I'm confused.  I thought core/layout/api was for consumption by things outside
of layout?  Why would ScrollAnchor need to use it?

[commit-bot: I haz the power, 2016-05-04 15:57:03]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-05-04 15:58:06]

Description was changed from

==========
[Layout API] Start converting ScrollAnchor to new layout API

There were several references to a static method, scrollerLayoutBox,
which returns a raw LayoutBox*, which is deprecated by the new layout API.
I can't convert all the references at once because there is a long chain
of reference passing to unwind, so I (TEMPORARILY) duplicated the method
to create scrollerLayoutBoxItem() and started converting the easy
references to use that instead.

There are no functional changes.

BUG=499321
==========

to

==========
[Layout API] Start converting ScrollAnchor to new layout API

There were several references to a static method, scrollerLayoutBox,
which returns a raw LayoutBox*, which is deprecated by the new layout API.
I can't convert all the references at once because there is a long chain
of reference passing to unwind, so I (TEMPORARILY) duplicated the method
to create scrollerLayoutBoxItem() and started converting the easy
references to use that instead.

There are no functional changes.

BUG=499321

Committed: https://crrev.com/a313736960ccd0293046b192a3ea41aa4d2ae78f
Cr-Commit-Position: refs/heads/master@{#391522}
==========

[commit-bot: I haz the power, 2016-05-04 15:58:07]

Patchset 1 (id:??) landed as
https://crrev.com/a313736960ccd0293046b192a3ea41aa4d2ae78f
Cr-Commit-Position: refs/heads/master@{#391522}

[pilgrim_google, 2016-05-04 16:23:22]

On 2016/05/04 at 15:50:39, skobes wrote:
> I'm confused.  I thought core/layout/api was for consumption by things outside
of layout?  Why would ScrollAnchor need to use it?

Because it's using a method on FrameView that returns a raw LayoutBox*, and I'm
trying to get rid of that method.

[skobes, 2016-05-04 16:35:38]

On 2016/05/04 16:23:22, pilgrim_google wrote:
> On 2016/05/04 at 15:50:39, skobes wrote:
> > I'm confused.  I thought core/layout/api was for consumption by things
outside
> of layout?  Why would ScrollAnchor need to use it?
> 
> Because it's using a method on FrameView that returns a raw LayoutBox*, and
I'm
> trying to get rid of that method.

Hmm ok.  Sounds like root layer scrolling may improve this.  Will a
PaintLayerScrollableArea still be able to provide its LayoutBox*?