Extend file-system abstraction with a couple methods, remove context

Extend file-system abstraction with a couple methods, remove context.

New methods:
 - exists: I'll be using it for input validation among other things
 - lastModified: I'll be using this on some utilities to support the incremental
 API.

BUG=
R=paulberry@google.com

Committed: https://github.com/dart-lang/sdk/commit/99ab24f628b23f248582874a6987883ab76c3195
Committed: https://github.com/dart-lang/sdk/commit/102de9e476bcd2b17f35604a7a3e442b28e14194
Committed: https://github.com/dart-lang/sdk/commit/f8fbff73225729f720e951253400ce6adf2aa083

[Siggi Cherem (dart-lang), 2017-04-26 23:33:23]

Description was changed from

==========
Extend file-system abstraction with a couple methods.

New methods:
 - exists: I'll be using it for input validation among other things
 - lastModified: I'll be using this on some utilities to support the incremental
 API.

BUG=
==========

to

==========
Extend file-system abstraction with a couple methods, remove context.

New methods:
 - exists: I'll be using it for input validation among other things
 - lastModified: I'll be using this on some utilities to support the incremental
 API.

BUG=
==========

[Siggi Cherem (dart-lang), 2017-04-27 00:07:16]

Patchset #1 (id:1) has been deleted

[Siggi Cherem (dart-lang), 2017-04-27 00:07:26]

Patchset #1 (id:20001) has been deleted

[Siggi Cherem (dart-lang), 2017-04-27 00:08:50]

sigmund@google.com changed reviewers:
+ paulberry@google.com

[Siggi Cherem (dart-lang), 2017-04-27 00:08:50]

https://codereview.chromium.org/2844903002/diff/40001/pkg/front_end/lib/file_...
File pkg/front_end/lib/file_system.dart (left):

https://codereview.chromium.org/2844903002/diff/40001/pkg/front_end/lib/file_...
pkg/front_end/lib/file_system.dart:24: path.Context get context;
I can split this change if you prefer, but very soon will be gone one way or
another. Because I did it this early I had to update the kernel_generator to
directly use uri.toFilePath(), which is not perfect. I'll be changing
kernel_generator in the next couple days to make it use fasta anyways, so I'm ok
with that temporary change.

[Paul Berry, 2017-04-27 13:12:18]

lgtm

[Siggi Cherem (dart-lang), 2017-04-27 21:01:15]

Description was changed from

==========
Extend file-system abstraction with a couple methods, remove context.

New methods:
 - exists: I'll be using it for input validation among other things
 - lastModified: I'll be using this on some utilities to support the incremental
 API.

BUG=
==========

to

==========
Extend file-system abstraction with a couple methods, remove context.

New methods:
 - exists: I'll be using it for input validation among other things
 - lastModified: I'll be using this on some utilities to support the incremental
 API.

BUG=
R=paulberry@google.com

Committed:
https://github.com/dart-lang/sdk/commit/99ab24f628b23f248582874a6987883ab76c3195
==========

[Siggi Cherem (dart-lang), 2017-04-27 21:01:17]

Committed patchset #1 (id:40001) manually as
99ab24f628b23f248582874a6987883ab76c3195 (presubmit successful).

[Siggi Cherem (dart-lang), 2017-04-27 22:05:16]

Description was changed from

==========
Extend file-system abstraction with a couple methods, remove context.

New methods:
 - exists: I'll be using it for input validation among other things
 - lastModified: I'll be using this on some utilities to support the incremental
 API.

BUG=
R=paulberry@google.com

Committed:
https://github.com/dart-lang/sdk/commit/99ab24f628b23f248582874a6987883ab76c3195
==========

to

==========
Extend file-system abstraction with a couple methods, remove context.

New methods:
 - exists: I'll be using it for input validation among other things
 - lastModified: I'll be using this on some utilities to support the incremental
 API.

BUG=
R=paulberry@google.com

Committed:
https://github.com/dart-lang/sdk/commit/99ab24f628b23f248582874a6987883ab76c3195
Committed:
https://github.com/dart-lang/sdk/commit/102de9e476bcd2b17f35604a7a3e442b28e14194
==========

[Siggi Cherem (dart-lang), 2017-04-27 22:05:17]

Committed patchset #2 (id:60001) manually as
102de9e476bcd2b17f35604a7a3e442b28e14194 (presubmit successful).

[Siggi Cherem (dart-lang), 2017-04-28 22:57:12]

Description was changed from

==========
Extend file-system abstraction with a couple methods, remove context.

New methods:
 - exists: I'll be using it for input validation among other things
 - lastModified: I'll be using this on some utilities to support the incremental
 API.

BUG=
R=paulberry@google.com

Committed:
https://github.com/dart-lang/sdk/commit/99ab24f628b23f248582874a6987883ab76c3195
Committed:
https://github.com/dart-lang/sdk/commit/102de9e476bcd2b17f35604a7a3e442b28e14194
==========

to

==========
Extend file-system abstraction with a couple methods, remove context.

New methods:
 - exists: I'll be using it for input validation among other things
 - lastModified: I'll be using this on some utilities to support the incremental
 API.

BUG=
R=paulberry@google.com

Committed:
https://github.com/dart-lang/sdk/commit/99ab24f628b23f248582874a6987883ab76c3195
Committed:
https://github.com/dart-lang/sdk/commit/102de9e476bcd2b17f35604a7a3e442b28e14194
Committed:
https://github.com/dart-lang/sdk/commit/f8fbff73225729f720e951253400ce6adf2aa083
==========

[Siggi Cherem (dart-lang), 2017-04-28 22:57:13]

Committed patchset #2 (id:60001) manually as
f8fbff73225729f720e951253400ce6adf2aa083 (presubmit successful).