Support self-referential package: imports with Pub.

Support self-referential package: imports with Pub.

Committed: https://code.google.com/p/dart/source/detail?r=11334

[Bob Nystrom, 2012-08-24 00:58:49]

Couple of nits, but LGTM.

When this goes in, please send a "BREAKING CHANGE" email to the list telling
everyone they need to add a "name" property to their pubspecs. But also that in
turn that lets them use "package:" to import stuff from their own package.

https://chromiumcodereview.appspot.com/10874051/diff/1/utils/pub/entrypoint.dart
File utils/pub/entrypoint.dart (right):

https://chromiumcodereview.appspot.com/10874051/diff/1/utils/pub/entrypoint.d...
utils/pub/entrypoint.dart:215: throw '"pubspec.yaml" not found.';
We should do friendly error messages here. Something like "Could not find a
'pubspec.yaml' file in the directory <path>.".

Also add a TODO to mention "pub init" in the error when that's implemented.

https://chromiumcodereview.appspot.com/10874051/diff/1/utils/pub/entrypoint.d...
utils/pub/entrypoint.dart:221: throw '"pubspec.yaml" must contain a "name"
key.';
Make this a friendly complete sentence, please.

[nweiz, 2012-08-24 01:12:12]

https://chromiumcodereview.appspot.com/10874051/diff/1/utils/pub/entrypoint.dart
File utils/pub/entrypoint.dart (right):

https://chromiumcodereview.appspot.com/10874051/diff/1/utils/pub/entrypoint.d...
utils/pub/entrypoint.dart:215: throw '"pubspec.yaml" not found.';
On 2012/08/24 00:58:49, Bob Nystrom wrote:
> We should do friendly error messages here. Something like "Could not find a
> 'pubspec.yaml' file in the directory <path>.".
> 
> Also add a TODO to mention "pub init" in the error when that's implemented.

Done.

https://chromiumcodereview.appspot.com/10874051/diff/1/utils/pub/entrypoint.d...
utils/pub/entrypoint.dart:221: throw '"pubspec.yaml" must contain a "name"
key.';
On 2012/08/24 00:58:49, Bob Nystrom wrote:
> Make this a friendly complete sentence, please.

This one is a complete sentence. I'd be happy to rewrite it, but I'm not sure
how best to do so.