Base: Make base::File use ScopedFD on POSIX.

Base: Make base::File use ScopedFD on POSIX.

Now that ScopedFD lives outside of file_util, File can use it to remove manual
lifetime management.

This also standarizes the behavior on Close failures for all platforms.

BUG=none

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=257562

[rvargas (doing something else), 2014-03-17 18:38:48]

PTAL

https://codereview.chromium.org/201083002/diff/1/base/files/file_posix.cc
File base/files/file_posix.cc (right):

https://codereview.chromium.org/201083002/diff/1/base/files/file_posix.cc#new...
base/files/file_posix.cc:210: return file_.is_valid();
This is interesting, as the current code considers any negative value as
invalid, but ScopedFD only considers -5 to be a valid FD.

This file will not store intentionally an invalid value on file_, but the API
allows callers to instantiate this object with a FD, so it is possible to hit
this case.

Maybe we need something else on ScopedFD?

[rvargas (doing something else), 2014-03-17 18:40:46]

https://codereview.chromium.org/201083002/diff/1/base/files/file_posix.cc
File base/files/file_posix.cc (right):

https://codereview.chromium.org/201083002/diff/1/base/files/file_posix.cc#new...
base/files/file_posix.cc:210: return file_.is_valid();
On 2014/03/17 18:38:49, rvargas wrote:
> invalid, but ScopedFD only considers -5 to be a valid FD.

I meant, "ScopedFD considers -5 to be a valid FD", as in -1 is the only invalid
value.

[brettw, 2014-03-17 19:38:50]

LGTM.

My patch was reverted and just relanded in case you notice weird sync problems.

https://codereview.chromium.org/201083002/diff/1/base/files/file_posix.cc
File base/files/file_posix.cc (right):

https://codereview.chromium.org/201083002/diff/1/base/files/file_posix.cc#new...
base/files/file_posix.cc:210: return file_.is_valid();
I thought about this but it seems that the system libraries only really return
-1, so how you could get something like -5 floating around would indicate a
pretty big error. Maybe File should assert that it's positive or -1?

[rvargas (doing something else), 2014-03-17 21:39:27]

Thanks!

https://codereview.chromium.org/201083002/diff/1/base/files/file_posix.cc
File base/files/file_posix.cc (right):

https://codereview.chromium.org/201083002/diff/1/base/files/file_posix.cc#new...
base/files/file_posix.cc:210: return file_.is_valid();
On 2014/03/17 19:38:50, brettw wrote:
> I thought about this but it seems that the system libraries only really return
> -1, so how you could get something like -5 floating around would indicate a
> pretty big error. Maybe File should assert that it's positive or -1?

OK. I added a dcheck on that constructor.

[rvargas (doing something else), 2014-03-17 21:53:53]

The CQ bit was checked by rvargas@chromium.org

[commit-bot: I haz the power, 2014-03-17 22:03:15]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/rvargas@chromium.org/201083002/40001

[commit-bot: I haz the power, 2014-03-18 00:47:55]

Change committed as 257562