Improve performance of HTMLSelectElement::resetToDefaultSelection().

Improve performance of HTMLSelectElement::resetToDefaultSelection().

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=620142, 624220
Committed: https://crrev.com/454e5952a2623d05d272939c01b4b09535be40a3
Cr-Commit-Position: refs/heads/master@{#402767}

[tkent, 2016-06-29 04:45:55]

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

[tkent, 2016-06-29 04:45:56]

Keishi, would you review this please?

https://codereview.chromium.org/2110003002/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/html/HTMLSelectElement.cpp (right):

https://codereview.chromium.org/2110003002/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/html/HTMLSelectElement.cpp:880:
selectOption(firstEnabledOption, firstEnabledOptionIndex, reason ==
ResetReasonSelectedOptionRemoved ? 0 : DeselectOtherOptions);
This is the main change.

[keishi, 2016-06-29 08:54:10]

LGTM

[tkent, 2016-06-29 08:58:33]

The CQ bit was checked by tkent@chromium.org

[commit-bot: I haz the power, 2016-06-29 08:58:49]

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, 2016-06-29 10:12:36]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-06-29 10:13:47]

Description was changed from

==========
Improve performance of HTMLSelectElement::resetToDefaultSelection().

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=620142, 624220
==========

to

==========
Improve performance of HTMLSelectElement::resetToDefaultSelection().

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=620142, 624220

Committed: https://crrev.com/454e5952a2623d05d272939c01b4b09535be40a3
Cr-Commit-Position: refs/heads/master@{#402767}
==========

[commit-bot: I haz the power, 2016-06-29 10:13:48]

Patchset 1 (id:??) landed as
https://crrev.com/454e5952a2623d05d272939c01b4b09535be40a3
Cr-Commit-Position: refs/heads/master@{#402767}