Fix possible race with batch updates in Files app.

Fix possible race with batch updates in Files app.

It's unlikely but possible that beginBatchUpdates() is executed on another list
thatn endBatchUpdates(). As a result, one of the lists will become unusable.

TEST=Tested manually with a fakely added delay for end-update-files.
BUG=234039
Committed: https://crrev.com/8176b73b02e137a3c06afb7382a0a277338cc5ea
Cr-Commit-Position: refs/heads/master@{#294545}

[mtomasz, 2014-09-11 08:36:54]

mtomasz@chromium.org changed reviewers:
+ hirono@chromium.org

[mtomasz, 2014-09-11 08:37:02]

@hirono: PTAL. Thanks.

[hirono, 2014-09-11 12:42:25]

https://codereview.chromium.org/560273002/diff/1/ui/file_manager/file_manager...
File ui/file_manager/file_manager/foreground/js/file_manager.js (right):

https://codereview.chromium.org/560273002/diff/1/ui/file_manager/file_manager...
ui/file_manager/file_manager/foreground/js/file_manager.js:827: var
listBeingUpdated = this.currentList_;
Is it needed to assign value here?

https://codereview.chromium.org/560273002/diff/1/ui/file_manager/file_manager...
ui/file_manager/file_manager/foreground/js/file_manager.js:836:
listBeingUpdated.endBatchUpdates();
How about assigning null here?

[mtomasz, 2014-09-12 02:59:38]

https://codereview.chromium.org/560273002/diff/1/ui/file_manager/file_manager...
File ui/file_manager/file_manager/foreground/js/file_manager.js (right):

https://codereview.chromium.org/560273002/diff/1/ui/file_manager/file_manager...
ui/file_manager/file_manager/foreground/js/file_manager.js:827: var
listBeingUpdated = this.currentList_;
On 2014/09/11 12:42:25, hirono wrote:
> Is it needed to assign value here?

Done.

https://codereview.chromium.org/560273002/diff/1/ui/file_manager/file_manager...
ui/file_manager/file_manager/foreground/js/file_manager.js:836:
listBeingUpdated.endBatchUpdates();
On 2014/09/11 12:42:25, hirono wrote:
> How about assigning null here?

Done.

[hirono, 2014-09-12 03:17:37]

lgtm!

[mtomasz, 2014-09-12 04:59:24]

The CQ bit was checked by mtomasz@chromium.org

[commit-bot: I haz the power, 2014-09-12 05:00:30]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patchset/560273002/40001

[commit-bot: I haz the power, 2014-09-12 05:45:31]

Committed patchset #3 (id:40001) as be51ba90179cd6e9f836cd86d25079699ed27afc

[commit-bot: I haz the power, 2014-09-12 05:48:33]

Patchset 3 (id:??) landed as
https://crrev.com/8176b73b02e137a3c06afb7382a0a277338cc5ea
Cr-Commit-Position: refs/heads/master@{#294545}