Add DCHECKs for catching inconsistent custom element state

Add DCHECKs for catching inconsistent custom element state

Without the bug fix by https://codereview.chromium.org/2297853006,
in the synchronous element creation path, an element could become
"custom" state without its definition.
Adding DCHECKs to catch any regression for the case.

With the previous bugfix rolled back, the following tests crashed
with these DCHECKs.

custom-elements/imports/attribute-changed-callback.html
custom-elements/imports/sync-create-element-order.html

BUG=642839
Committed: https://crrev.com/bc636d23f40160f384f451a91c265aa1bbe2915b
Cr-Commit-Position: refs/heads/master@{#416211}

[kochi, 2016-09-02 05:56:44]

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

[commit-bot: I haz the power, 2016-09-02 05:56:59]

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

[kochi, 2016-09-02 06:38:20]

Description was changed from

==========
Add DCHECKs for catching inconsistent custom element state

Without the bug fix by https://codereview.chromium.org/2297853006,
in the synchronous element creation path, an element could become
"custom" state without its definition (actually existed, but was
running the code path that should not have the definition).
Adding DCHECKs to catch any regression for the case.

With the previous bugfix rolled back, the following tests crashed
with these DCHECKs.

custom-elements/imports/attribute-changed-callback.html
custom-elements/imports/sync-create-element-order.html

BUG=642839
==========

to

==========
Add DCHECKs for catching inconsistent custom element state

Without the bug fix by https://codereview.chromium.org/2297853006,
in the synchronous element creation path, an element could become
"custom" state without its definition.
Adding DCHECKs to catch any regression for the case.

With the previous bugfix rolled back, the following tests crashed
with these DCHECKs.

custom-elements/imports/attribute-changed-callback.html
custom-elements/imports/sync-create-element-order.html

BUG=642839
==========

[kochi, 2016-09-02 06:38:21]

kochi@chromium.org changed reviewers:
+ dominicc@chromium.org

[kochi, 2016-09-02 06:38:51]

PTAL

[commit-bot: I haz the power, 2016-09-02 07:23:53]

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

[commit-bot: I haz the power, 2016-09-02 07:23:55]

Dry run: This issue passed the CQ dry run.

[dominicc (has gone to gerrit), 2016-09-02 07:49:35]

The CQ bit was checked by dominicc@chromium.org

[dominicc (has gone to gerrit), 2016-09-02 07:49:35]

lgtm

[commit-bot: I haz the power, 2016-09-02 07:49:52]

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, 2016-09-02 07:52:49]

Description was changed from

==========
Add DCHECKs for catching inconsistent custom element state

Without the bug fix by https://codereview.chromium.org/2297853006,
in the synchronous element creation path, an element could become
"custom" state without its definition.
Adding DCHECKs to catch any regression for the case.

With the previous bugfix rolled back, the following tests crashed
with these DCHECKs.

custom-elements/imports/attribute-changed-callback.html
custom-elements/imports/sync-create-element-order.html

BUG=642839
==========

to

==========
Add DCHECKs for catching inconsistent custom element state

Without the bug fix by https://codereview.chromium.org/2297853006,
in the synchronous element creation path, an element could become
"custom" state without its definition.
Adding DCHECKs to catch any regression for the case.

With the previous bugfix rolled back, the following tests crashed
with these DCHECKs.

custom-elements/imports/attribute-changed-callback.html
custom-elements/imports/sync-create-element-order.html

BUG=642839
==========

[commit-bot: I haz the power, 2016-09-02 07:52:50]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-09-02 07:55:28]

Description was changed from

==========
Add DCHECKs for catching inconsistent custom element state

Without the bug fix by https://codereview.chromium.org/2297853006,
in the synchronous element creation path, an element could become
"custom" state without its definition.
Adding DCHECKs to catch any regression for the case.

With the previous bugfix rolled back, the following tests crashed
with these DCHECKs.

custom-elements/imports/attribute-changed-callback.html
custom-elements/imports/sync-create-element-order.html

BUG=642839
==========

to

==========
Add DCHECKs for catching inconsistent custom element state

Without the bug fix by https://codereview.chromium.org/2297853006,
in the synchronous element creation path, an element could become
"custom" state without its definition.
Adding DCHECKs to catch any regression for the case.

With the previous bugfix rolled back, the following tests crashed
with these DCHECKs.

custom-elements/imports/attribute-changed-callback.html
custom-elements/imports/sync-create-element-order.html

BUG=642839

Committed: https://crrev.com/bc636d23f40160f384f451a91c265aa1bbe2915b
Cr-Commit-Position: refs/heads/master@{#416211}
==========

[commit-bot: I haz the power, 2016-09-02 07:55:29]

Patchset 1 (id:??) landed as
https://crrev.com/bc636d23f40160f384f451a91c265aa1bbe2915b
Cr-Commit-Position: refs/heads/master@{#416211}