Make sure to check for OS errors when constructing Uri.base

Make sure to check for OS errors when constructing Uri.base

R=iposva@google.com
BUG=http://dartbug.com/22649

Committed: https://code.google.com/p/dart/source/detail?r=44256

[Søren Gjesse, 2015-03-04 12:48:13]

https://codereview.chromium.org/980603002/diff/20001/runtime/bin/builtin.dart
File runtime/bin/builtin.dart (right):

https://codereview.chromium.org/980603002/diff/20001/runtime/bin/builtin.dart...
runtime/bin/builtin.dart:116: Uri _uriBase() {
We could also do this, if we care about not allocating one Directory object in
this case. I don't think we need to.

  // We are not using Dircetory.current here to avoid allocating a
  // Directory object.
  var result = _getCurrentDirectoryPath();
  if (result is OSError) {
    throw new FileSystemException(
        "Getting current working directory failed", "", result);
  }
  return new Uri.file(result + "/");

[Ivan Posva, 2015-03-04 17:36:25]

LGTM with comment.

-Ivan

https://codereview.chromium.org/980603002/diff/20001/runtime/bin/builtin.dart
File runtime/bin/builtin.dart (right):

https://codereview.chromium.org/980603002/diff/20001/runtime/bin/builtin.dart...
runtime/bin/builtin.dart:116: Uri _uriBase() {
On 2015/03/04 12:48:13, Søren Gjesse wrote:
> We could also do this, if we care about not allocating one Directory object in
> this case. I don't think we need to.
> 
>   // We are not using Dircetory.current here to avoid allocating a
>   // Directory object.
>   var result = _getCurrentDirectoryPath();
>   if (result is OSError) {
>     throw new FileSystemException(
>         "Getting current working directory failed", "", result);
>   }
>   return new Uri.file(result + "/");

By using Directory.current you need to import "dart:io" which we have the goal
to remove. So please use the alternate code. Thanks!

[Søren Gjesse, 2015-03-05 10:27:02]

Committed patchset #2 (id:20001) manually as 44256 (presubmit successful).