Fix crash when scrolling in a remote process frame

Fix crash when scrolling in a remote process frame

This is occurring because we try to get the RootScrollerController from the top
level Document by calling topDocument(). Since we're in a remote Frame though,
topDocument returns the current RootScrollerController's Document and so we
infinitely recurse into isViewportScrollCallback.

This is a quick fix to the problem while I come up with a better long term
solution for OOPIFs.

BUG=641775
Committed: https://crrev.com/5e3154ffb1fc384d3a1529a3c5aa91ae83e50473
Cr-Commit-Position: refs/heads/master@{#415348}

[bokan, 2016-08-30 15:28:24]

The CQ bit was checked by bokan@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-08-30 15:28:41]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[bokan, 2016-08-30 15:29:38]

Description was changed from

==========
Fix crash when scrolling in a remote process frame

This is occurring because we try to get the RootScrollerController from the top
level Document by calling topDocument(). Since we're in a remote Frame though,
topDocument returns the current RootScrollerController's Document and so we
infinitely recurse into isViewportScrollCallback.

This is a quick fix to the problem while I come up with a better long term
solution for OOPIFs.

BUG=641775
==========

to

==========
Fix crash when scrolling in a remote process frame

This is occurring because we try to get the RootScrollerController from the top
level Document by calling topDocument(). Since we're in a remote Frame though,
topDocument returns the current RootScrollerController's Document and so we
infinitely recurse into isViewportScrollCallback.

This is a quick fix to the problem while I come up with a better long term
solution for OOPIFs.

BUG=641775
==========

[bokan, 2016-08-30 15:29:38]

bokan@chromium.org changed reviewers:
+ lfg@chromium.org

[bokan, 2016-08-30 15:30:59]

This seems to fix the issue for me. I was getting a sad tab crash without any
output in the console rather than a hang/100% CPU usage, so feel free to
confirm.

I'll add some OOPIF tests to RootScrollerTests in a followup today but I'd like
to get this fixed asap.

[lfg, 2016-08-30 15:41:20]

lgtm.

nit: can you add a TODO() with a link to the bug?

On 2016/08/30 15:30:59, bokan wrote:
> This seems to fix the issue for me. I was getting a sad tab crash without any
> output in the console rather than a hang/100% CPU usage, so feel free to
> confirm.

That seems correct, in release builds, the recursion is tail-call optimized,
so we get the hang/100% cpu.

> I'll add some OOPIF tests to RootScrollerTests in a followup today but I'd
like
> to get this fixed asap.

Sounds good.

[bokan, 2016-08-30 16:11:31]

On 2016/08/30 15:41:20, lfg wrote:
> lgtm.
> 
> nit: can you add a TODO() with a link to the bug?

Done. Filed crbug.com/642378 for OOPIFing the rootScroller proposal.

[bokan, 2016-08-30 16:11:35]

The CQ bit was checked by bokan@chromium.org

[bokan, 2016-08-30 16:11:36]

The patchset sent to the CQ was uploaded after l-g-t-m from lfg@chromium.org
Link to the patchset: https://codereview.chromium.org/2290353002/#ps20001
(title: "Added TODOs")

[commit-bot: I haz the power, 2016-08-30 16:12:05]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-08-30 17:58:15]

Description was changed from

==========
Fix crash when scrolling in a remote process frame

This is occurring because we try to get the RootScrollerController from the top
level Document by calling topDocument(). Since we're in a remote Frame though,
topDocument returns the current RootScrollerController's Document and so we
infinitely recurse into isViewportScrollCallback.

This is a quick fix to the problem while I come up with a better long term
solution for OOPIFs.

BUG=641775
==========

to

==========
Fix crash when scrolling in a remote process frame

This is occurring because we try to get the RootScrollerController from the top
level Document by calling topDocument(). Since we're in a remote Frame though,
topDocument returns the current RootScrollerController's Document and so we
infinitely recurse into isViewportScrollCallback.

This is a quick fix to the problem while I come up with a better long term
solution for OOPIFs.

BUG=641775
==========

[commit-bot: I haz the power, 2016-08-30 17:58:16]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-08-30 18:01:16]

Description was changed from

==========
Fix crash when scrolling in a remote process frame

This is occurring because we try to get the RootScrollerController from the top
level Document by calling topDocument(). Since we're in a remote Frame though,
topDocument returns the current RootScrollerController's Document and so we
infinitely recurse into isViewportScrollCallback.

This is a quick fix to the problem while I come up with a better long term
solution for OOPIFs.

BUG=641775
==========

to

==========
Fix crash when scrolling in a remote process frame

This is occurring because we try to get the RootScrollerController from the top
level Document by calling topDocument(). Since we're in a remote Frame though,
topDocument returns the current RootScrollerController's Document and so we
infinitely recurse into isViewportScrollCallback.

This is a quick fix to the problem while I come up with a better long term
solution for OOPIFs.

BUG=641775

Committed: https://crrev.com/5e3154ffb1fc384d3a1529a3c5aa91ae83e50473
Cr-Commit-Position: refs/heads/master@{#415348}
==========

[commit-bot: I haz the power, 2016-08-30 18:01:17]

Patchset 2 (id:??) landed as
https://crrev.com/5e3154ffb1fc384d3a1529a3c5aa91ae83e50473
Cr-Commit-Position: refs/heads/master@{#415348}