Make core/editing/ files to match Blink coding style

Make core/editing/ files to match Blink coding style

This patch makes files in "core/editing/" to match Blink coding style and
formatting comments, near style changes, to fit 80 characters to ease of working
these files in the future for improving code health.

Note: Naming related style violation will be addressed in other patches to
reduce size of patches.

This patch is also a preparation of moving execCommand related files,
http://crrev.com/1294543005

BUG=509257
TEST=n/a; no behavior changes

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=200687

[yosin_UTC9, 2015-08-18 02:09:32]

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

[yosin_UTC9, 2015-08-18 02:11:12]

PTAL

[tkent, 2015-08-18 02:25:43]

The CQ bit was checked by tkent@chromium.org

[tkent, 2015-08-18 02:25:44]

lgtm

[commit-bot: I haz the power, 2015-08-18 02:26:02]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1292303005/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1292303005/1

[commit-bot: I haz the power, 2015-08-18 04:23:03]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=200687

[Nico, 2015-08-18 04:50:33]

thakis@chromium.org changed reviewers:
+ thakis@chromium.org

[Nico, 2015-08-18 04:50:34]

wrong bug #