Updated ddbg to use new streams API.

Updated ddbg to use new streams API.
Committed: https://code.google.com/p/dart/source/detail?r=19086

[Tom Ball, 2013-02-26 01:05:16]

Fixed ddbg.dart to work with new IO API. 

Søren, I don't know if you're the best person to review this, but you last
touched tests/standalone/debugger/debug_lib.dart, which I used as an example.
That may be just because you merged the branch, in which case please forward to
who is most appropriate.

[Tom Ball, 2013-02-26 01:09:56]

One question/issue I found: I had to add an exit(0) to quitShell(), which
previously wasn't necessary. What's a better solution?

[Søren Gjesse, 2013-02-26 15:40:04]

lgtm

https://codereview.chromium.org/12315097/diff/1/tools/ddbg.dart
File tools/ddbg.dart (right):

https://codereview.chromium.org/12315097/diff/1/tools/ddbg.dart#newcode61
tools/ddbg.dart:61: exit(0);
As you mentioned this looks wrong. What should work is to get the subscription
in the stringStream.listen below, and the cancel this subscription here.

However there is a bug in StringDecoder which was fixed in
https://code.google.com/p/dart/source/detail?r=19046, so make sure to use that
revision for trying it out.

[hausner, 2013-02-26 17:43:53]

LGTM assuming it works. Might be good to do some one-off testing by making the
test fail and see whether the code properly cleans up processes.

[Tom Ball, 2013-02-26 18:18:53]

https://codereview.chromium.org/12315097/diff/1/tools/ddbg.dart
File tools/ddbg.dart (right):

https://codereview.chromium.org/12315097/diff/1/tools/ddbg.dart#newcode61
tools/ddbg.dart:61: exit(0);
On 2013/02/26 15:40:04, Søren Gjesse wrote:
> As you mentioned this looks wrong. What should work is to get the subscription
> in the stringStream.listen below, and the cancel this subscription here.
> 
> However there is a bug in StringDecoder which was fixed in
> https://code.google.com/p/dart/source/detail?r=19046, so make sure to use that
> revision for trying it out.

I made the change you suggested and sync'd to 19061, but the main isolate is
still waiting due to one remaining live port.  Any suggestions on how I can
debug which port/variable this is?

[Tom Ball, 2013-02-26 21:53:53]

Committed patchset #2 manually as r19086 (presubmit successful).