Fix nested 'unicode-bidi: isolate' can cause infinite loop

Fix nested 'unicode-bidi: isolate' can cause infinite loop

This patch fixes constructBidiRunsForLine() to handle the nested
'unicode-bidi: isolate' runs with the correct containing isolate.

crbug.com/274717 fixed the nested case by updating currentRoot to the
root of the last nested runs. While this fixed simple cases, it does
not set the correct root when nested in multiple levels.

The wrong root can let highestContainingIsolateWithinRoot() to find
ancestors up to the root elements. This will find ancestors that were
already processed, and results in an infinite loop.

BUG=520282
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=201847

[kojii, 2015-09-02 06:57:20]

kojii@chromium.org changed reviewers:
+ eae@chromium.org, leviw@chromium.org

[kojii, 2015-09-02 08:46:08]

PTAL.

[eae, 2015-09-04 18:31:56]

LGTM w/nit

Thanks!

https://codereview.chromium.org/1328633002/diff/20001/Source/core/layout/Bidi...
File Source/core/layout/BidiRunForLine.cpp (right):

https://codereview.chromium.org/1328633002/diff/20001/Source/core/layout/Bidi...
Source/core/layout/BidiRunForLine.cpp:144: LayoutObject* root;
Could you mark this const?

[kojii, 2015-09-06 01:19:28]

The CQ bit was checked by kojii@chromium.org

[kojii, 2015-09-06 01:19:28]

The patchset sent to the CQ was uploaded after l-g-t-m from eae@chromium.org
Link to the patchset: https://codereview.chromium.org/1328633002/#ps40001
(title: "Add const (eae's nit)")

[commit-bot: I haz the power, 2015-09-06 01:19:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1328633002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1328633002/40001

[commit-bot: I haz the power, 2015-09-06 01:24:13]

Committed patchset #3 (id:40001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=201847