[fuchsia] Fix build. Build packages/ output. Add Directory::Exists().

[fuchsia] Fix build. Build packages/ output. Add Directory::Exists().

The build was broken by the addition of OS::MaxRSS, which I've added
unimplemented. I need the packages/ output to get the Dart language
tests going. I've added Directory::Exists() so that we can give
the right error message on a missing package: import instead of
crashing.

R=asiva@google.com

Committed: https://github.com/dart-lang/sdk/commit/1b303e64fecc7f438f3a9db3d879f7b3f8d43c26

[zra, 2016-08-17 21:53:52]

zra@google.com changed reviewers:
+ asiva@google.com

[siva, 2016-08-18 01:40:55]

list_pkg_directories.py seems to have no changes why do you have it in the list?

LGTM with that one comment.

[zra, 2016-08-18 14:50:23]

On 2016/08/18 01:40:55, siva wrote:
> list_pkg_directories.py seems to have no changes why do you have it in the
list?
> 
> LGTM with that one comment.

I set the executable bit so that the script can be invoked from GN.

[zra, 2016-08-18 16:21:17]

Description was changed from

==========
[fuchsia] Fix build. Build packages/ output. Add Directory::Exists().

The build was broken by the addition of OS::MaxRSS, which I've added
unimplemented. I need the packages/ output to get the Dart language
tests going. I've added Directory::Exists() so that we can give
the right error message on a missing package: import instead of
crashing.
==========

to

==========
[fuchsia] Fix build. Build packages/ output. Add Directory::Exists().

The build was broken by the addition of OS::MaxRSS, which I've added
unimplemented. I need the packages/ output to get the Dart language
tests going. I've added Directory::Exists() so that we can give
the right error message on a missing package: import instead of
crashing.

R=asiva@google.com

Committed:
https://github.com/dart-lang/sdk/commit/1b303e64fecc7f438f3a9db3d879f7b3f8d43c26
==========

[zra, 2016-08-18 16:21:19]

Committed patchset #1 (id:1) manually as
1b303e64fecc7f438f3a9db3d879f7b3f8d43c26 (presubmit successful).