IDL: Auto-declare implied methods only if not otherwise declared

IDL: Auto-declare implied methods only if not otherwise declared

An interface with an iterable<>, maplike<> or setlike<> declaration
should according to WebIDL have a number of additional methods, some
of which we already auto-declare.

Adjust this auto-declaration so that it's disabled if the interface
has an explicitly declared method with the same name already. This
allows an interface to override some or all of the implied methods,
and for instance declare them with different extended attributes.

BUG=432683
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=189805

[Jens Widell, 2015-02-09 11:02:58]

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

[Jens Widell, 2015-02-09 11:02:59]

PTAL

[haraken, 2015-02-09 11:31:29]

LGTM

[Jens Widell, 2015-02-09 11:32:50]

The CQ bit was checked by jl@opera.com

[commit-bot: I haz the power, 2015-02-09 11:34:05]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/894693005/20001

[Yuki, 2015-02-09 12:44:22]

lgtm

[commit-bot: I haz the power, 2015-02-09 13:49:43]

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

[commit-bot: I haz the power, 2015-02-09 13:49:45]

Try jobs failed on following builders:
  win_gpu on tryserver.chromium.gpu (JOB_TIMED_OUT,
http://build.chromium.org/p/tryserver.chromium.gpu/builders/win_gpu/builds/12...)
Timed out jobs are not retried to avoid causing additional load on the builders
with large pending queues.

[Jens Widell, 2015-02-09 13:54:05]

The CQ bit was checked by jl@opera.com

[commit-bot: I haz the power, 2015-02-09 13:55:07]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/894693005/20001

[commit-bot: I haz the power, 2015-02-09 14:28:06]

Committed patchset #2 (id:20001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=189805