Merge "Improve performance of HTMLSelectElement::resetToDefaultSelection()." to M52.

Merge "Improve performance of HTMLSelectElement::resetToDefaultSelection()." to M52.

If we remove a selected OPTION from a SELECT element, selectOption() called from
resetToDefaultSelection() doesn't need to call deselectItemsWithoutValidation()
because there are no other selected OPTIONs.

- !multiple() doesn't imply DeselectOtherOptions.  Updates existing callsites of
  selectOption().
- Make SelectOptionFlags mandatory.

Removing 20,000 OPTIONs: 6,348ms -> 5,324ms

BUG=624220
Review-Url: https://codereview.chromium.org/2110003002
Cr-Commit-Position: refs/heads/master@{#402767}
(cherry picked from commit 454e5952a2623d05d272939c01b4b09535be40a3)

Committed: https://chromium.googlesource.com/chromium/src/+/6fa87e050f4dcf0b0c54704b6916a0568d496c71

[tkent, 2016-07-01 05:57:48]

Description was changed from

==========
Merge "Improve performance of HTMLSelectElement::resetToDefaultSelection()." to
M52.

If we remove a selected OPTION from a SELECT element, selectOption() called from
resetToDefaultSelection() doesn't need to call deselectItemsWithoutValidation()
because there are no other selected OPTIONs.

- !multiple() doesn't imply DeselectOtherOptions.  Updates existing callsites of
  selectOption().
- Make SelectOptionFlags mandatory.

Removing 20,000 OPTIONs: 6,348ms -> 5,324ms

BUG=624220

Review-Url: https://codereview.chromium.org/2110003002
Cr-Commit-Position: refs/heads/master@{#402767}
(cherry picked from commit 454e5952a2623d05d272939c01b4b09535be40a3)
==========

to

==========
Merge "Improve performance of HTMLSelectElement::resetToDefaultSelection()." to
M52.

If we remove a selected OPTION from a SELECT element, selectOption() called from
resetToDefaultSelection() doesn't need to call deselectItemsWithoutValidation()
because there are no other selected OPTIONs.

- !multiple() doesn't imply DeselectOtherOptions.  Updates existing callsites of
  selectOption().
- Make SelectOptionFlags mandatory.

Removing 20,000 OPTIONs: 6,348ms -> 5,324ms

BUG=624220

Review-Url: https://codereview.chromium.org/2110003002
Cr-Commit-Position: refs/heads/master@{#402767}
(cherry picked from commit 454e5952a2623d05d272939c01b4b09535be40a3)

Committed:
https://chromium.googlesource.com/chromium/src/+/6fa87e050f4dcf0b0c54704b6916...
==========

[tkent, 2016-07-01 05:57:51]

Committed patchset #1 (id:1) manually as
6fa87e050f4dcf0b0c54704b6916a0568d496c71.