Introduce a struct to store arguments of Element::focus().

Introduce a struct to store arguments of Element::focus().

Also, converts the |restorePreviousSelection| argument to an enum class.
This CL has no behavior changes, and improves code readability.

BUG=526516
Committed: https://crrev.com/7e0e1b14e1033e03fa1dc772e2c44dfb45a7888b
Cr-Commit-Position: refs/heads/master@{#358859}

[tkent, 2015-11-10 14:28:37]

Description was changed from

==========
Introduce a struct to store arguments of Element::focus().

BUG=
==========

to

==========
Introduce a struct to store arguments of Element::focus().

Also, converts the |restorePreviousSelection| argument to an enum class.
This CL has no behavior changes, and improves code readability.

BUG=526516
==========

[tkent, 2015-11-10 14:29:59]

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

[tkent, 2015-11-10 14:29:59]

kochi@, would you review this please?
This is a preparation of crbug.com/526516, and I'll apply FocusParams to more
functions in following CLs.

[kochi, 2015-11-10 17:21:22]

The CQ bit was checked by kochi@chromium.org

[kochi, 2015-11-10 17:21:23]

lgtm

[commit-bot: I haz the power, 2015-11-10 17:21:42]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1420693006/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1420693006/1

[commit-bot: I haz the power, 2015-11-10 18:35:59]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-10 18:36:56]

Patchset 1 (id:??) landed as
https://crrev.com/7e0e1b14e1033e03fa1dc772e2c44dfb45a7888b
Cr-Commit-Position: refs/heads/master@{#358859}