Don't compile io_service if io is not supported.

Don't compile io_service if io is not supported.

BUG=
R=whesse@google.com

Committed: https://code.google.com/p/dart/source/detail?r=27890

[Bill Hesse, 2013-09-25 16:25:54]

https://codereview.chromium.org/24612002/diff/2/runtime/bin/io_impl_sources.gypi
File runtime/bin/io_impl_sources.gypi (right):

https://codereview.chromium.org/24612002/diff/2/runtime/bin/io_impl_sources.g...
runtime/bin/io_impl_sources.gypi:63: 'secure_socket_unsupported.cc',
Add io_service_unsupported.cc here.

But the problem may be that when the dartium snapshot is built, this has been
compiled, but File and Directory (used by snapshot_gen) will call it probably.

[Anders Johnsen, 2013-09-25 16:29:02]

Sync IO calls are still available.

https://codereview.chromium.org/24612002/diff/2/runtime/bin/io_impl_sources.gypi
File runtime/bin/io_impl_sources.gypi (right):

https://codereview.chromium.org/24612002/diff/2/runtime/bin/io_impl_sources.g...
runtime/bin/io_impl_sources.gypi:63: 'secure_socket_unsupported.cc',
On 2013/09/25 16:25:54, Bill Hesse wrote:
> Add io_service_unsupported.cc here.
> 
> But the problem may be that when the dartium snapshot is built, this has been
> compiled, but File and Directory (used by snapshot_gen) will call it probably.

Done.

[Bill Hesse, 2013-09-25 16:29:35]

lgtm

[Anders Johnsen, 2013-09-25 16:31:30]

Committed patchset #3 manually as r27890 (presubmit successful).