Reland of Fix several corner case issues of scrollbar paint invalidation

Reland of Fix several corner case issues of scrollbar paint invalidation (patchset #1 id:1 of https://codereview.chromium.org/1513573004/ )

Reason for revert:
Thanks for looking after the health of Oilpan builds. But as Oilpan is yet to be CQ-blocking, we don't want to be unnecessarily causing post-landing revert consternation & be in the way of overall progress.

Hence, I'm going to undo this revert & address the problem the Oilpan static checks are picking up on; it's a trivial one.

Original issue's description:
> Revert of Fix several corner case issues of scrollbar paint invalidation (patchset #7 id:120001 of https://codereview.chromium.org/1491193003/ )
>
> Reason for revert:
> I suspect this may have broken the Oilpan build:
>
> https://build.chromium.org/p/chromium.webkit/builders/WebKit%20Mac%20Oilpan/builds/27442
>
> Original issue's description:
> > Fix several corner case issues of scrollbar paint invalidation
> >
> > - Invalidate composited scrollbars also during paint invalidation to
> >   avoid unnecessary invalidation on intermediate changes;
> >
> > - Invalidate also on the containing box for moved/resized composited
> >   non-overlay scrollbars. This ensures the expanded/shrunk areas of the
> >   box because of scrollbar existence/width change are invalidated. This
> >   is the root cause of bug 535161.
> >
> > - Avoid unnecessary invalidations on overlay scrollbar changes.
> >
> > BUG=535161, 560418
> >
> > Committed: https://crrev.com/48e402acbebf2717b8e79b89dba5310d31bf95da
> > Cr-Commit-Position: refs/heads/master@{#363998}
>
> TBR=chrishtr@chromium.org,skobes@chromium.org,wangxianzhu@chromium.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=535161, 560418
>
> Committed: https://crrev.com/ed0577e5a8952de3976d6b18fa0ed39fe2a0e418
> Cr-Commit-Position: refs/heads/master@{#364000}

TBR=chrishtr@chromium.org,skobes@chromium.org,wangxianzhu@chromium.org,dominicc@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=535161, 560418
Committed: https://crrev.com/435854e8b327de68a00cdbec8d7e6c6f07658cbe
Cr-Commit-Position: refs/heads/master@{#364006}

[sof, 2015-12-09 08:25:59]

Created Reland of Fix several corner case issues of scrollbar paint invalidation

[commit-bot: I haz the power, 2015-12-09 08:27:12]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1511143002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1511143002/1

[commit-bot: I haz the power, 2015-12-09 08:29:39]

Description was changed from

==========
Reland of Fix several corner case issues of scrollbar paint invalidation
(patchset #1 id:1 of https://codereview.chromium.org/1513573004/ )

Reason for revert:
Thanks for looking after the health of Oilpan builds. But as Oilpan is yet to be
CQ-blocking, we don't want to be unnecessarily causing post-landing revert
consternation & be in the way of overall progress.

Hence, I'm going to undo this revert & address the problem the Oilpan static
checks are picking up on; it's a trivial one.

Original issue's description:
> Revert of Fix several corner case issues of scrollbar paint invalidation
(patchset #7 id:120001 of https://codereview.chromium.org/1491193003/ )
> 
> Reason for revert:
> I suspect this may have broken the Oilpan build:
> 
>
https://build.chromium.org/p/chromium.webkit/builders/WebKit%20Mac%20Oilpan/b...
> 
> Original issue's description:
> > Fix several corner case issues of scrollbar paint invalidation
> >
> > - Invalidate composited scrollbars also during paint invalidation to
> >   avoid unnecessary invalidation on intermediate changes;
> >
> > - Invalidate also on the containing box for moved/resized composited
> >   non-overlay scrollbars. This ensures the expanded/shrunk areas of the
> >   box because of scrollbar existence/width change are invalidated. This
> >   is the root cause of bug 535161.
> >
> > - Avoid unnecessary invalidations on overlay scrollbar changes.
> >
> > BUG=535161,560418
> >
> > Committed: https://crrev.com/48e402acbebf2717b8e79b89dba5310d31bf95da
> > Cr-Commit-Position: refs/heads/master@{#363998}
> 
> TBR=chrishtr@chromium.org,skobes@chromium.org,wangxianzhu@chromium.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=535161,560418
> 
> Committed: https://crrev.com/ed0577e5a8952de3976d6b18fa0ed39fe2a0e418
> Cr-Commit-Position: refs/heads/master@{#364000}

TBR=chrishtr@chromium.org,skobes@chromium.org,wangxianzhu@chromium.org,domini...
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=535161,560418
==========

to

==========
Reland of Fix several corner case issues of scrollbar paint invalidation
(patchset #1 id:1 of https://codereview.chromium.org/1513573004/ )

Reason for revert:
Thanks for looking after the health of Oilpan builds. But as Oilpan is yet to be
CQ-blocking, we don't want to be unnecessarily causing post-landing revert
consternation & be in the way of overall progress.

Hence, I'm going to undo this revert & address the problem the Oilpan static
checks are picking up on; it's a trivial one.

Original issue's description:
> Revert of Fix several corner case issues of scrollbar paint invalidation
(patchset #7 id:120001 of https://codereview.chromium.org/1491193003/ )
> 
> Reason for revert:
> I suspect this may have broken the Oilpan build:
> 
>
https://build.chromium.org/p/chromium.webkit/builders/WebKit%20Mac%20Oilpan/b...
> 
> Original issue's description:
> > Fix several corner case issues of scrollbar paint invalidation
> >
> > - Invalidate composited scrollbars also during paint invalidation to
> >   avoid unnecessary invalidation on intermediate changes;
> >
> > - Invalidate also on the containing box for moved/resized composited
> >   non-overlay scrollbars. This ensures the expanded/shrunk areas of the
> >   box because of scrollbar existence/width change are invalidated. This
> >   is the root cause of bug 535161.
> >
> > - Avoid unnecessary invalidations on overlay scrollbar changes.
> >
> > BUG=535161,560418
> >
> > Committed: https://crrev.com/48e402acbebf2717b8e79b89dba5310d31bf95da
> > Cr-Commit-Position: refs/heads/master@{#363998}
> 
> TBR=chrishtr@chromium.org,skobes@chromium.org,wangxianzhu@chromium.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=535161,560418
> 
> Committed: https://crrev.com/ed0577e5a8952de3976d6b18fa0ed39fe2a0e418
> Cr-Commit-Position: refs/heads/master@{#364000}

TBR=chrishtr@chromium.org,skobes@chromium.org,wangxianzhu@chromium.org,domini...
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=535161,560418
==========

[commit-bot: I haz the power, 2015-12-09 08:29:40]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-12-09 08:30:21]

Description was changed from

==========
Reland of Fix several corner case issues of scrollbar paint invalidation
(patchset #1 id:1 of https://codereview.chromium.org/1513573004/ )

Reason for revert:
Thanks for looking after the health of Oilpan builds. But as Oilpan is yet to be
CQ-blocking, we don't want to be unnecessarily causing post-landing revert
consternation & be in the way of overall progress.

Hence, I'm going to undo this revert & address the problem the Oilpan static
checks are picking up on; it's a trivial one.

Original issue's description:
> Revert of Fix several corner case issues of scrollbar paint invalidation
(patchset #7 id:120001 of https://codereview.chromium.org/1491193003/ )
> 
> Reason for revert:
> I suspect this may have broken the Oilpan build:
> 
>
https://build.chromium.org/p/chromium.webkit/builders/WebKit%20Mac%20Oilpan/b...
> 
> Original issue's description:
> > Fix several corner case issues of scrollbar paint invalidation
> >
> > - Invalidate composited scrollbars also during paint invalidation to
> >   avoid unnecessary invalidation on intermediate changes;
> >
> > - Invalidate also on the containing box for moved/resized composited
> >   non-overlay scrollbars. This ensures the expanded/shrunk areas of the
> >   box because of scrollbar existence/width change are invalidated. This
> >   is the root cause of bug 535161.
> >
> > - Avoid unnecessary invalidations on overlay scrollbar changes.
> >
> > BUG=535161,560418
> >
> > Committed: https://crrev.com/48e402acbebf2717b8e79b89dba5310d31bf95da
> > Cr-Commit-Position: refs/heads/master@{#363998}
> 
> TBR=chrishtr@chromium.org,skobes@chromium.org,wangxianzhu@chromium.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=535161,560418
> 
> Committed: https://crrev.com/ed0577e5a8952de3976d6b18fa0ed39fe2a0e418
> Cr-Commit-Position: refs/heads/master@{#364000}

TBR=chrishtr@chromium.org,skobes@chromium.org,wangxianzhu@chromium.org,domini...
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=535161,560418
==========

to

==========
Reland of Fix several corner case issues of scrollbar paint invalidation
(patchset #1 id:1 of https://codereview.chromium.org/1513573004/ )

Reason for revert:
Thanks for looking after the health of Oilpan builds. But as Oilpan is yet to be
CQ-blocking, we don't want to be unnecessarily causing post-landing revert
consternation & be in the way of overall progress.

Hence, I'm going to undo this revert & address the problem the Oilpan static
checks are picking up on; it's a trivial one.

Original issue's description:
> Revert of Fix several corner case issues of scrollbar paint invalidation
(patchset #7 id:120001 of https://codereview.chromium.org/1491193003/ )
>
> Reason for revert:
> I suspect this may have broken the Oilpan build:
>
>
https://build.chromium.org/p/chromium.webkit/builders/WebKit%20Mac%20Oilpan/b...
>
> Original issue's description:
> > Fix several corner case issues of scrollbar paint invalidation
> >
> > - Invalidate composited scrollbars also during paint invalidation to
> >   avoid unnecessary invalidation on intermediate changes;
> >
> > - Invalidate also on the containing box for moved/resized composited
> >   non-overlay scrollbars. This ensures the expanded/shrunk areas of the
> >   box because of scrollbar existence/width change are invalidated. This
> >   is the root cause of bug 535161.
> >
> > - Avoid unnecessary invalidations on overlay scrollbar changes.
> >
> > BUG=535161,560418
> >
> > Committed: https://crrev.com/48e402acbebf2717b8e79b89dba5310d31bf95da
> > Cr-Commit-Position: refs/heads/master@{#363998}
>
> TBR=chrishtr@chromium.org,skobes@chromium.org,wangxianzhu@chromium.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=535161,560418
>
> Committed: https://crrev.com/ed0577e5a8952de3976d6b18fa0ed39fe2a0e418
> Cr-Commit-Position: refs/heads/master@{#364000}

TBR=chrishtr@chromium.org,skobes@chromium.org,wangxianzhu@chromium.org,domini...
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=535161,560418

Committed: https://crrev.com/435854e8b327de68a00cdbec8d7e6c6f07658cbe
Cr-Commit-Position: refs/heads/master@{#364006}
==========

[commit-bot: I haz the power, 2015-12-09 08:30:22]

Patchset 1 (id:??) landed as
https://crrev.com/435854e8b327de68a00cdbec8d7e6c6f07658cbe
Cr-Commit-Position: refs/heads/master@{#364006}