Add multiple results and timeout handling to the Mac OS mDNS native extension

Add multiple results and timeout handling to the Mac OS mDNS native extension

The mDNS native extension on Mac OS now keeps sending results until the
given timeout period has expired.

To make that happen changed the thread pumping the results to use select on the
privided file descriptor for the given timeout period.

R=wibling@google.com, karlklose@google.com
BUG=

Committed: https://github.com/dart-lang/fletch/commit/5c4d55e13f559d010b9294b14fc2eb6e6fbb9660

[Søren Gjesse, 2015-11-10 10:15:30]

This is based on top of https://codereview.chromium.org/1411063006/.

There is no new sha1 file for the binary yet. I will add that when the review is
otherwise final.

[wibling, 2015-11-10 14:44:56]

wibling@google.com changed reviewers:
+ wibling@google.com

[wibling, 2015-11-10 14:44:56]

lgtm

https://codereview.chromium.org/1416833009/diff/1/src/pkg/mdns/mdns_extension...
File src/pkg/mdns/mdns_extension_macos.cc (right):

https://codereview.chromium.org/1416833009/diff/1/src/pkg/mdns/mdns_extension...
src/pkg/mdns/mdns_extension_macos.cc:88: result =
DNSServiceProcessResult(ctx->ref);
NIT: Merge the two above lines into one.

[Søren Gjesse, 2015-11-10 15:22:40]

Committed patchset #2 (id:20001) manually as
5c4d55e13f559d010b9294b14fc2eb6e6fbb9660.

[Søren Gjesse, 2015-11-10 15:30:05]

https://codereview.chromium.org/1416833009/diff/1/src/pkg/mdns/mdns_extension...
File src/pkg/mdns/mdns_extension_macos.cc (right):

https://codereview.chromium.org/1416833009/diff/1/src/pkg/mdns/mdns_extension...
src/pkg/mdns/mdns_extension_macos.cc:88: result =
DNSServiceProcessResult(ctx->ref);
On 2015/11/10 14:44:56, wibling wrote:
> NIT: Merge the two above lines into one.

Done.

[karlklose, 2015-11-12 10:37:07]

LGTM.

https://codereview.chromium.org/1416833009/diff/20001/pkg/mdns/test/decode_te...
File pkg/mdns/test/decode_test.dart (right):

https://codereview.chromium.org/1416833009/diff/20001/pkg/mdns/test/decode_te...
pkg/mdns/test/decode_test.dart:34: RR 16 [0]
These tests already test PTR, SRV, and TXT decoding, but they use
ResourceRecord.toString() instead. I think we should unify the way we test this.