Reapply dart:io API changes.

Reapply dart:io API changes.

R=sgjesse@google.com
BUG=
TEST=

Committed: https://code.google.com/p/dart/source/detail?r=4790

[srdjan, 2012-03-01 18:08:07]

https://chromiumcodereview.appspot.com/9568004/diff/1001/runtime/bin/socket.dart
File runtime/bin/socket.dart (right):

https://chromiumcodereview.appspot.com/9568004/diff/1001/runtime/bin/socket.d...
runtime/bin/socket.dart:21: void set onError(void callback());
Can we pass argument to the callback telling something about the error? How do
we figure out what error occurred?

[Søren Gjesse, 2012-03-01 20:26:42]

https://chromiumcodereview.appspot.com/9568004/diff/1001/runtime/bin/socket.dart
File runtime/bin/socket.dart (right):

https://chromiumcodereview.appspot.com/9568004/diff/1001/runtime/bin/socket.d...
runtime/bin/socket.dart:21: void set onError(void callback());
On 2012/03/01 18:08:07, srdjan wrote:
> Can we pass argument to the callback telling something about the error? How do
> we figure out what error occurred?

The error handling/reporting in dart:io is still something we need to work on.
It is on the OKRs for this quater. My suggestion is to have all the onError
callbacks receive an Exception object (probably SocketException here) which is
the exception that would have been thrown had the operation been synchronous.