Fix resource leak (temporary files and directories) in run-bindings-tests

Fix resource leak (temporary files and directories) in run-bindings-tests

run-bindings-tests is leaking files and directories on Windows,
breaking the Windows try bot.
This CL fixes it.

In Python, resources should be managed with the 'with' statement,
with resources released in __exit__ methods.
Using __del__ statements and scope does not work, as __del__ is not
guaranteed to be called.

run-bindings-tests uses a class, ScopedTempFileProvider,
whose resources are incorrectly managed with __del__, hence the problem.

References:
[blink-dev] RFC: simplifying Blink CQ, switching fully to SimpleTryJobVerifier
https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/5ArYZHC_QR8
https://groups.google.com/a/chromium.org/d/msg/blink-dev/5ArYZHC_QR8/NmFQZrkAlYUJ

http://docs.python.org/2/reference/datamodel.html#object.__del__
"It is not guaranteed that__del__() methods are called for objects
that still exist when the interpreter exits."

With Statement:
http://docs.python.org/2/reference/compound_stmts.html#with
http://docs.python.org/2/reference/datamodel.html#with-statement-context-managers

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=167773

[Nils Barth (inactive), 2014-02-25 01:37:26]

Fix to (one) of the Windows try bot issues!

[haraken, 2014-02-25 01:45:12]

LGTM

https://codereview.chromium.org/179253002/diff/20001/Tools/Scripts/webkitpy/b...
File Tools/Scripts/webkitpy/bindings/main.py (right):

https://codereview.chromium.org/179253002/diff/20001/Tools/Scripts/webkitpy/b...
Tools/Scripts/webkitpy/bindings/main.py:69: self.dir_paths = []

Instead of managing all file handles, file paths and directory paths, how about
preparing one temporary directory and creating files/directories in the
temporary directory? Then we just need to call rmtree for the temporary
directory at shutdown.

I'm OK with landing the CL without the fix (since it's more important to fix the
win bot issue asap), but you might want to consider the fix in a follow up.

[Nils Barth (inactive), 2014-02-25 01:49:03]

https://codereview.chromium.org/179253002/diff/20001/Tools/Scripts/webkitpy/b...
File Tools/Scripts/webkitpy/bindings/main.py (right):

https://codereview.chromium.org/179253002/diff/20001/Tools/Scripts/webkitpy/b...
Tools/Scripts/webkitpy/bindings/main.py:69: self.dir_paths = []
On 2014/02/25 01:45:13, haraken wrote:
> Instead of managing all file handles, file paths and directory paths, how
about
> preparing one temporary directory and creating files/directories in the
> temporary directory? Then we just need to call rmtree for the temporary
> directory at shutdown.

That's a good point; the value of using new_temp_file is that the intermediate
files can be anonymous.
Anyway, once I finish refactoring compute_interfaces_info
(was 'compute_dependencies'), almost all of these other temporary
files will go away, so it'll be less of an issue.
Once those land, I'll take another look.

[Nils Barth (inactive), 2014-02-25 01:49:16]

The CQ bit was checked by nbarth@chromium.org

[commit-bot: I haz the power, 2014-02-25 01:49:25]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/nbarth@chromium.org/179253002/40001

[Nils Barth (inactive), 2014-02-25 01:57:57]

https://codereview.chromium.org/179253002/diff/20001/Tools/Scripts/webkitpy/b...
File Tools/Scripts/webkitpy/bindings/main.py (right):

https://codereview.chromium.org/179253002/diff/20001/Tools/Scripts/webkitpy/b...
Tools/Scripts/webkitpy/bindings/main.py:69: self.dir_paths = []
Actually, Terry is fixing r-b-t so we don't need temporary files:
call Python directly, instead of via a separate process,
so can pass the data directly.

This lets us avoid temporary files, and even output files,
which completely avoids any file problems!
(...and any OS-specific issues.)

[commit-bot: I haz the power, 2014-02-25 05:19:27]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/nbarth@chromium.org/179253002/40001

[commit-bot: I haz the power, 2014-02-25 07:41:16]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/nbarth@chromium.org/179253002/40001

[commit-bot: I haz the power, 2014-02-25 13:25:12]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/nbarth@chromium.org/179253002/40001

[commit-bot: I haz the power, 2014-02-25 14:36:54]

Change committed as 167773