Avoid WTF::Vector::at() and operator[] in core/dom.

Avoid WTF::Vector::at() and operator[] in core/dom.

at() and operator[] are slow due to RELEASE_ASSERT. We can avoid the slowness by
range-based |for|.

This CL has no behavior changes except runtime performance.

BUG=668300
Committed: https://crrev.com/a9f3df455d2ea2b360dda396e86df6fdff49dbe8
Cr-Commit-Position: refs/heads/master@{#436875}

[tkent, 2016-12-07 01:08:08]

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

[commit-bot: I haz the power, 2016-12-07 01:08:50]

Dry run: 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, 2016-12-07 02:06:26]

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

[commit-bot: I haz the power, 2016-12-07 02:06:26]

Dry run: Try jobs failed on following builders:
  android_n5x_swarming_rel on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/android_n5x_...)

[tkent, 2016-12-07 02:28:47]

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

[commit-bot: I haz the power, 2016-12-07 02:29:14]

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

[tkent, 2016-12-07 02:57:38]

Patchset #1 (id:1) has been deleted

[tkent, 2016-12-07 04:57:29]

Description was changed from

==========
Avoid WTF::Vector::at() and operator[] in core/dom.

at() and operator[] are slow due to RELEASE_ASSERT. We can avoid the slowness by
range-based |for|.

BUG=668300
==========

to

==========
Avoid WTF::Vector::at() and operator[] in core/dom.

at() and operator[] are slow due to RELEASE_ASSERT. We can avoid the slowness by
range-based |for|.

This CL has no behavior changes except runtime performance.

BUG=668300
==========

[tkent, 2016-12-07 04:57:45]

tkent@chromium.org changed reviewers:
+ hayato@chromium.org

[tkent, 2016-12-07 04:57:46]

hayato@, would you review this please?

[hayato, 2016-12-07 04:58:50]

lgtm

[commit-bot: I haz the power, 2016-12-07 05:41:07]

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

[commit-bot: I haz the power, 2016-12-07 05:41:08]

Dry run: This issue passed the CQ dry run.

[tkent, 2016-12-07 05:48:56]

The CQ bit was checked by tkent@chromium.org

[commit-bot: I haz the power, 2016-12-07 05:49:13]

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, 2016-12-07 05:53:07]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1481089736422800,
"parent_rev": "bce496b7dd17fcf898a8538ccac6c264a584d544", "commit_rev":
"39d22e7fa436966cf7ba61c30b3ad0c8694ffee6"}

[commit-bot: I haz the power, 2016-12-07 05:53:44]

Committed patchset #1 (id:20001)

[commit-bot: I haz the power, 2016-12-07 05:57:54]

Description was changed from

==========
Avoid WTF::Vector::at() and operator[] in core/dom.

at() and operator[] are slow due to RELEASE_ASSERT. We can avoid the slowness by
range-based |for|.

This CL has no behavior changes except runtime performance.

BUG=668300
==========

to

==========
Avoid WTF::Vector::at() and operator[] in core/dom.

at() and operator[] are slow due to RELEASE_ASSERT. We can avoid the slowness by
range-based |for|.

This CL has no behavior changes except runtime performance.

BUG=668300

Committed: https://crrev.com/a9f3df455d2ea2b360dda396e86df6fdff49dbe8
Cr-Commit-Position: refs/heads/master@{#436875}
==========

[commit-bot: I haz the power, 2016-12-07 05:57:55]

Patchset 1 (id:??) landed as
https://crrev.com/a9f3df455d2ea2b360dda396e86df6fdff49dbe8
Cr-Commit-Position: refs/heads/master@{#436875}