Add README.md to dom/html-related directories in LayoutTests.

Add README.md to dom/html-related directories in LayoutTests.

BUG=685886
NOTRY=true

Review-Url: https://codereview.chromium.org/2682623002
Cr-Commit-Position: refs/heads/master@{#448573}
Committed: https://chromium.googlesource.com/chromium/src/+/28ac5a462c714b6cd7fda6e8d433723d3bcbe9f3

[tkent, 2017-02-07 08:14:49]

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

[tkent, 2017-02-07 08:14:49]

kochi-san, would you review this please?

[kochi, 2017-02-07 08:30:49]

LGTM

[tkent, 2017-02-07 08:45:02]

The CQ bit was checked by tkent@chromium.org

[tkent, 2017-02-07 08:45:02]

The patchset sent to the CQ was uploaded after l-g-t-m from kochi@chromium.org
Link to the patchset: https://codereview.chromium.org/2682623002/#ps20001
(title: "Add newlines at end of files.")

[commit-bot: I haz the power, 2017-02-07 08:45:14]

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, 2017-02-07 08:49:11]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1486457102197920,
"parent_rev": "58397dcb1baf7977349645311d2e9d8c6a593375", "commit_rev":
"28ac5a462c714b6cd7fda6e8d433723d3bcbe9f3"}

[commit-bot: I haz the power, 2017-02-07 08:49:48]

Description was changed from

==========
Add README.md to dom/html-related directories in LayoutTests.

BUG=685886
NOTRY=true
==========

to

==========
Add README.md to dom/html-related directories in LayoutTests.

BUG=685886
NOTRY=true

Review-Url: https://codereview.chromium.org/2682623002
Cr-Commit-Position: refs/heads/master@{#448573}
Committed:
https://chromium.googlesource.com/chromium/src/+/28ac5a462c714b6cd7fda6e8d433...
==========

[commit-bot: I haz the power, 2017-02-07 08:49:49]

Committed patchset #2 (id:20001) as
https://chromium.googlesource.com/chromium/src/+/28ac5a462c714b6cd7fda6e8d433...