Fix a crash when pseudo elements are used for a shadow host

Fix a crash when pseudo elements are used for a shadow host

LayoutTreeBuilderTraversal should not pass a before/after pseudo element to
FlatTreeTraversal because FlatTreeTraversal can not handle it correctly.

Because there are still other clients which pass a pseudo element to
FlatTreTraversal, we can not update Node::canParticipateInFlatTree()'s condition,
which is used in FlatTreeTraversal::assertPreCondition(). That would be done as
another task.

BUG=637003
Committed: https://crrev.com/66b2cb7e218c15404eced5cab488718b3a0e537d
Cr-Commit-Position: refs/heads/master@{#413072}

[hayato, 2016-08-18 12:23:56]

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

[commit-bot: I haz the power, 2016-08-18 12:24:14]

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

[hayato, 2016-08-18 12:25:19]

Description was changed from

==========
Fix a crash when pseudo elements are used for a shadow host

Quick fix for a crash when pseudo element are used for a shadow host.

The root cause of the crash is that LayoutTreeBuilder is passing a pseudo
element to FlatTreeTraversal. However, it needs non-trivial efforts to stop
that by re-architecting LayoutTreeBuilder.

For a while, FlatTreeTravesal should handle a pseudo elemenet in its
FlatTreeTraversal::traverseSiblings() as it already does in its
FlatTreeTraversal::traverseParent().

BUG=637003
==========

to

==========
Fix a crash when pseudo elements are used for a shadow host

Quick fix for a crash when pseudo element are used for a shadow host.

The root cause of the crash is that LayoutTreeBuilder is passing a pseudo
element to FlatTreeTraversal. However, it needs non-trivial efforts to stop
this behavior because it needs re-architecting LayoutTreeBuilder.

For a while, FlatTreeTraversal should handle a pseudo element in its
FlatTreeTraversal::traverseSiblings(), as it already does in
FlatTreeTraversal::traverseParent().

BUG=637003
==========

[hayato, 2016-08-18 12:26:34]

Add a test

[hayato, 2016-08-18 12:26:36]

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

[commit-bot: I haz the power, 2016-08-18 12:26:52]

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

[hayato, 2016-08-18 12:27:22]

hayato@chromium.org changed reviewers:
+ kochi@chromium.org, rune@opera.com

[hayato, 2016-08-18 12:27:22]

PTAL

[commit-bot: I haz the power, 2016-08-18 14:05:51]

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

[commit-bot: I haz the power, 2016-08-18 14:05:51]

Dry run: Try jobs failed on following builders:
  win_chromium_rel_ng on master.tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_...)

[rune, 2016-08-18 23:54:54]

https://codereview.chromium.org/2257053003/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/dom/shadow/FlatTreeTraversal.cpp (right):

https://codereview.chromium.org/2257053003/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/dom/shadow/FlatTreeTraversal.cpp:105: return
direction == TraversalDirectionForward ? node.nextSibling() :
node.previousSibling();
Shouldn't LayoutTreeBuilderTraversal handle pseudo elements before
FlatTreeTraversal is called if pseudo elements are not part of the flat tree?

I don't understand why FlatTreeTraversal::nextSibling() is called _before_ the
check for isAfterPseudoElement() in LayoutTreeBuilderTraversal::nextSibling().

Would moving isAfterPseudoElement before the nextSibling call fix this issue?

[hayato, 2016-08-19 03:50:35]

update

[hayato, 2016-08-19 03:50:37]

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

[commit-bot: I haz the power, 2016-08-19 03:50:57]

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

[hayato, 2016-08-19 03:55:22]

Description was changed from

==========
Fix a crash when pseudo elements are used for a shadow host

Quick fix for a crash when pseudo element are used for a shadow host.

The root cause of the crash is that LayoutTreeBuilder is passing a pseudo
element to FlatTreeTraversal. However, it needs non-trivial efforts to stop
this behavior because it needs re-architecting LayoutTreeBuilder.

For a while, FlatTreeTraversal should handle a pseudo element in its
FlatTreeTraversal::traverseSiblings(), as it already does in
FlatTreeTraversal::traverseParent().

BUG=637003
==========

to

==========
Fix a crash when pseudo elements are used for a shadow host

LayoutTreeBuilderTraversal should not pass a before/after pseudo element to
FlatTreeTraversal because FlatTreeTraversal can not handle it correctly.

Because there are still other clients which pass a pseudo element to
FlatTreTraversal, we can not update Node::canParticipateInFlatTree()'s
condition.
That would be done as another task.

BUG=637003
==========

[hayato, 2016-08-19 03:55:34]

Description was changed from

==========
Fix a crash when pseudo elements are used for a shadow host

LayoutTreeBuilderTraversal should not pass a before/after pseudo element to
FlatTreeTraversal because FlatTreeTraversal can not handle it correctly.

Because there are still other clients which pass a pseudo element to
FlatTreTraversal, we can not update Node::canParticipateInFlatTree()'s
condition.
That would be done as another task.

BUG=637003
==========

to

==========
Fix a crash when pseudo elements are used for a shadow host

LayoutTreeBuilderTraversal should not pass a before/after pseudo element to 
FlatTreeTraversal because FlatTreeTraversal can not handle it correctly.

Because there are still other clients which pass a pseudo element to
FlatTreTraversal, we can not update Node::canParticipateInFlatTree()'s
condition.
That would be done as another task.

BUG=637003
==========

[hayato, 2016-08-19 03:56:32]

Description was changed from

==========
Fix a crash when pseudo elements are used for a shadow host

LayoutTreeBuilderTraversal should not pass a before/after pseudo element to 
FlatTreeTraversal because FlatTreeTraversal can not handle it correctly.

Because there are still other clients which pass a pseudo element to
FlatTreTraversal, we can not update Node::canParticipateInFlatTree()'s
condition.
That would be done as another task.

BUG=637003
==========

to

==========
Fix a crash when pseudo elements are used for a shadow host

LayoutTreeBuilderTraversal should not pass a before/after pseudo element to 
FlatTreeTraversal because FlatTreeTraversal can not handle it correctly.

Because there are still other clients which pass a pseudo element to
FlatTreTraversal, we can not update Node::canParticipateInFlatTree()'s
condition,
which is used in FlatTreeTraversal::assertPreCondition(). That would be done as
another task.

BUG=637003
==========

[hayato, 2016-08-19 03:58:47]

https://codereview.chromium.org/2257053003/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/dom/shadow/FlatTreeTraversal.cpp (right):

https://codereview.chromium.org/2257053003/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/dom/shadow/FlatTreeTraversal.cpp:105: return
direction == TraversalDirectionForward ? node.nextSibling() :
node.previousSibling();
Good point! I missed LayoutTreeBuilderTraversal.

I have updated the CL.

[commit-bot: I haz the power, 2016-08-19 06:52:04]

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

[commit-bot: I haz the power, 2016-08-19 06:52:05]

Dry run: This issue passed the CQ dry run.

[rune, 2016-08-19 06:53:03]

lgtm

[hayato, 2016-08-19 06:55:06]

The CQ bit was checked by hayato@chromium.org

[commit-bot: I haz the power, 2016-08-19 06:55:24]

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, 2016-08-19 06:58:58]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-08-19 07:01:17]

Description was changed from

==========
Fix a crash when pseudo elements are used for a shadow host

LayoutTreeBuilderTraversal should not pass a before/after pseudo element to 
FlatTreeTraversal because FlatTreeTraversal can not handle it correctly.

Because there are still other clients which pass a pseudo element to
FlatTreTraversal, we can not update Node::canParticipateInFlatTree()'s
condition,
which is used in FlatTreeTraversal::assertPreCondition(). That would be done as
another task.

BUG=637003
==========

to

==========
Fix a crash when pseudo elements are used for a shadow host

LayoutTreeBuilderTraversal should not pass a before/after pseudo element to
FlatTreeTraversal because FlatTreeTraversal can not handle it correctly.

Because there are still other clients which pass a pseudo element to
FlatTreTraversal, we can not update Node::canParticipateInFlatTree()'s
condition,
which is used in FlatTreeTraversal::assertPreCondition(). That would be done as
another task.

BUG=637003

Committed: https://crrev.com/66b2cb7e218c15404eced5cab488718b3a0e537d
Cr-Commit-Position: refs/heads/master@{#413072}
==========

[commit-bot: I haz the power, 2016-08-19 07:01:18]

Patchset 3 (id:??) landed as
https://crrev.com/66b2cb7e218c15404eced5cab488718b3a0e537d
Cr-Commit-Position: refs/heads/master@{#413072}