Add Uri.directory constructor.

Add Uri.directory constructor.

Make Directory.uri getter use the new constructor.
This also fixes that the uri getter doesn't work correctly on Windows.

Add uri getter on file system entity.

BUG= http://dartbug.com/17065
R=sgjesse@google.com

Committed: https://code.google.com/p/dart/source/detail?r=45227

[Lasse Reichstein Nielsen, 2015-04-17 08:25:58]

lrn@google.com changed reviewers:
+ sgjesse@google.com

[Søren Gjesse, 2015-04-17 08:33:21]

lgtm

https://codereview.chromium.org/1089183004/diff/1/sdk/lib/core/uri.dart
File sdk/lib/core/uri.dart (right):

https://codereview.chromium.org/1089183004/diff/1/sdk/lib/core/uri.dart#newco...
sdk/lib/core/uri.dart:779: static _makeFileUri(String path, bool
slashTerminated) {
Optional named argument for documentation in the above use?

[Lasse Reichstein Nielsen, 2015-04-17 08:41:41]

https://codereview.chromium.org/1089183004/diff/1/sdk/lib/core/uri.dart
File sdk/lib/core/uri.dart (right):

https://codereview.chromium.org/1089183004/diff/1/sdk/lib/core/uri.dart#newco...
sdk/lib/core/uri.dart:779: static _makeFileUri(String path, bool
slashTerminated) {
No optional arguments for internal functions.
It's a waste of processor power to bother for something that is only used
internally.

[Lasse Reichstein Nielsen, 2015-04-17 08:56:13]

Committed patchset #2 (id:20001) manually as 45227 (presubmit successful).

[kevmoo, 2015-06-23 20:53:40]

On 2015/04/17 08:56:13, Lasse Reichstein Nielsen wrote:
> Committed patchset #2 (id:20001) manually as 45227 (presubmit successful).

Please update CHANGELOG.md when making API changes