Fix incorrect signature in socket.dart.

Fix incorrect signature in socket.dart.

R=vegorov@google.com

Committed: https://github.com/dart-lang/sdk/commit/7b3603878362917a22d74f6fa450f88a7b012cce

[ahe, 2017-03-16 13:03:58]

ahe@google.com changed reviewers:
+ vegorov@google.com

[ahe, 2017-03-16 13:03:59]

The file runtime/bin/socket_patch.dart says this:

  void joinMulticast(InternetAddress group, [NetworkInterface interface]) {
    _socket.joinMulticast(group, interface);
  }

  void leaveMulticast(InternetAddress group, [NetworkInterface interface]) {
    _socket.leaveMulticast(group, interface);
  }

I assume this means that it has always been a positional parameter as that's
what the concrete method actually says. I can't find any tests that use these
two methods, so we might never know what the intent was ;-)

[Vyacheslav Egorov (Google), 2017-03-16 13:10:25]

lgtm

[ahe, 2017-03-16 13:28:28]

Description was changed from

==========
Fix incorrect signature in socket.dart.
==========

to

==========
Fix incorrect signature in socket.dart.

R=vegorov@google.com

Committed:
https://github.com/dart-lang/sdk/commit/7b3603878362917a22d74f6fa450f88a7b012cce
==========

[ahe, 2017-03-16 13:28:30]

Committed patchset #1 (id:1) manually as
7b3603878362917a22d74f6fa450f88a7b012cce (presubmit successful).