Add websocket files to dummy io.dart implementation for dart2js.

Add websocket files to dummy io.dart implementation for dart2js.

Apparently this file is also used for generating API documentation
now. We need to move away from that and generate the API documentation
from the io_runtime.dart file in the SDK. The dummy implementation
file is not automatically updated and therefore this will keep
breaking.

R=ahe@google.com,rnystrom@google.com
BUG=
TEST=

Committed: https://code.google.com/p/dart/source/detail?r=7063

[ahe, 2012-04-27 09:27:45]

LGTM.

FWIW, as long as dart-sdk/lib/io/io_runtime.dart sources in files that are not
written in the Dart programming language, its going to be hard for apidoc to use
anything else. The same applies to the Dart Editor.

https://chromiumcodereview.appspot.com/10254001/diff/3001/runtime/bin/websock...
File runtime/bin/websocket.dart (right):

https://chromiumcodereview.appspot.com/10254001/diff/3001/runtime/bin/websock...
runtime/bin/websocket.dart:9: *     WebSocketHandler wsHandler = new
WebSocketHandler();
Code samples should be wrapped in [:CODE_HERE:].

[Mads Ager (google), 2012-04-27 09:29:50]

https://chromiumcodereview.appspot.com/10254001/diff/3001/runtime/bin/websock...
File runtime/bin/websocket.dart (right):

https://chromiumcodereview.appspot.com/10254001/diff/3001/runtime/bin/websock...
runtime/bin/websocket.dart:9: *     WebSocketHandler wsHandler = new
WebSocketHandler();
On 2012/04/27 09:27:45, ahe wrote:
> Code samples should be wrapped in [:CODE_HERE:].

Yes, I know. But that will look horrible with the current version of dartdoc. :(

[Bob Nystrom, 2012-04-27 18:06:37]

FYI

https://chromiumcodereview.appspot.com/10254001/diff/3001/runtime/bin/websock...
File runtime/bin/websocket.dart (right):

https://chromiumcodereview.appspot.com/10254001/diff/3001/runtime/bin/websock...
runtime/bin/websocket.dart:9: *     WebSocketHandler wsHandler = new
WebSocketHandler();
On 2012/04/27 09:29:50, Mads Ager wrote:
> On 2012/04/27 09:27:45, ahe wrote:
> > Code samples should be wrapped in [:CODE_HERE:].
> 
> Yes, I know. But that will look horrible with the current version of dartdoc.
:(

I think what Mads is doing here is fine. The indentation defines a code block in
markdown. Unlike [: ... :], I think, this also unambiguously lets dartdoc know
that it should be a <pre> code block and not <code>.