Aggregate consecutive rescan request as much as possible.

Aggregate consequtive rescan request as much as possible.

- Revived AsyncUtil.Aggregation, which was used to aggregate consecutive run requests into one.
- Aggregated consecutive re-scan request using the aggregator described above.
 
BUG=316050
TEST=confirmed manually

Committed: https://crrev.com/bc045e021aed1096e38ef912228951b548526c9d
Cr-Commit-Position: refs/heads/master@{#291846}

[fukino, 2014-08-25 06:51:54]

yoshiki@, could you take a look?

This CL improves only the copy for Downloads, not Drive.
But, for Downloads, this will improve performance considerably and reduce the
flicker.

[yoshiki, 2014-08-25 08:36:39]

https://codereview.chromium.org/488043003/diff/1/ui/file_manager/file_manager...
File ui/file_manager/file_manager/common/js/async_util.js (right):

https://codereview.chromium.org/488043003/diff/1/ui/file_manager/file_manager...
ui/file_manager/file_manager/common/js/async_util.js:263: * @param {boolean=}
opt_aggregate If true, consecutive calls are aggregated
It's better to create new class (eg. RateLimitterWithDiscard), rather than using
flag. The new-class way should be clearer.

And I prefer to the word 'discard' rather than 'aggregate', in order to
emphasize that it discards over-paced tasks.

https://codereview.chromium.org/488043003/diff/1/ui/file_manager/file_manager...
ui/file_manager/file_manager/common/js/async_util.js:336: this.lastRunTime_ =
Date.now();
If caller would continue to call this method many times in shorter time than the
interval, the closure would be never called. Is it intended?

I assume that lastRunTime should be updated in runImmediately instead of here.

[fukino, 2014-08-25 09:37:09]

https://codereview.chromium.org/488043003/diff/1/ui/file_manager/file_manager...
File ui/file_manager/file_manager/common/js/async_util.js (right):

https://codereview.chromium.org/488043003/diff/1/ui/file_manager/file_manager...
ui/file_manager/file_manager/common/js/async_util.js:263: * @param {boolean=}
opt_aggregate If true, consecutive calls are aggregated
On 2014/08/25 08:36:39, yoshiki wrote:
> It's better to create new class (eg. RateLimitterWithDiscard), rather than
using
> flag. The new-class way should be clearer.
> 
> And I prefer to the word 'discard' rather than 'aggregate', in order to
> emphasize that it discards over-paced tasks. 

Done.
I revived AsyncUtil.Aggregation, and rename it slightly as AsyncUtil.Aggregator
to be consistent with RateLimiter.

https://codereview.chromium.org/488043003/diff/1/ui/file_manager/file_manager...
ui/file_manager/file_manager/common/js/async_util.js:336: this.lastRunTime_ =
Date.now();
On 2014/08/25 08:36:39, yoshiki wrote:
> If caller would continue to call this method many times in shorter time than
the
> interval, the closure would be never called. Is it intended?
> 
> I assume that lastRunTime should be updated in runImmediately instead of here.

Yes, it is intended and I reused AsyncUtil.Aggragation for this purpose.

[yoshiki, 2014-08-25 13:44:59]

lgtm

[fukino, 2014-08-26 02:09:16]

The CQ bit was checked by fukino@chromium.org

[commit-bot: I haz the power, 2014-08-26 02:12:47]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/fukino@chromium.org/488043003/20001

[commit-bot: I haz the power, 2014-08-26 05:29:55]

Committed patchset #2 (20001) as 0b6f8f6e1c2f491c4b512a25dc5cf1acc75712ca

[commit-bot: I haz the power, 2014-09-10 02:40:42]

Patchset 2 (id:??) landed as
https://crrev.com/bc045e021aed1096e38ef912228951b548526c9d
Cr-Commit-Position: refs/heads/master@{#291846}