IDL: Improve overload resolution for methods with variadic arguments

IDL: Improve overload resolution for methods with variadic arguments

When calculating "optionality list" for a method (as part of calculating
the effective overload set), treat variadic arguments as optional instead
as required.

WebIDL defines the optionality list as a list of "required", "optional"
and "variadic", whereas we implement it as a list of booleans. A list of
booleans is enough to achieve correct behavior, assuming both "optional"
and "variadic" are considered to be optional (true).

BUG=293561
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=185289

[Jens Widell, 2014-11-13 09:31:14]

jl@opera.com changed reviewers:
+ haraken@chromium.org

[Jens Widell, 2014-11-13 09:31:15]

PTAL

[haraken, 2014-11-13 09:33:49]

LGTM

[Jens Widell, 2014-11-13 09:35:40]

The CQ bit was checked by jl@opera.com

[commit-bot: I haz the power, 2014-11-13 09:36:18]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/723013003/20001

[commit-bot: I haz the power, 2014-11-13 11:45:05]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-11-13 11:45:06]

Try jobs failed on following builders:
  win_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/win_blink_rel/builds/36294)

[Jens Widell, 2014-11-13 11:51:20]

The CQ bit was checked by jl@opera.com

[commit-bot: I haz the power, 2014-11-13 11:51:32]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/723013003/20001

[commit-bot: I haz the power, 2014-11-13 13:40:51]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-11-13 13:40:52]

Try jobs failed on following builders:
  win_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/win_blink_rel/builds/36318)

[Jens Widell, 2014-11-13 13:41:46]

The CQ bit was checked by jl@opera.com

[commit-bot: I haz the power, 2014-11-13 13:41:57]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/723013003/20001

[commit-bot: I haz the power, 2014-11-13 14:17:05]

Committed patchset #2 (id:20001) as 185289