[downloads] Remove DownloadManager::RemoveAllDownloads.

[downloads] Remove DownloadManager::RemoveAllDownloads.

This API was only being used by tests and most call sites were using it
incorrectly. Calling RemoveAllDownloads() immediately after creating a
DownloadManager is guaranteed to do nothing. Any new or persisted
downloads are added by some other entity asynchronously long after the
the DownloadManager has been created. In Chrome a DownloadManager starts
out empty until the downloads history DB is succuessfully queried.

In addition, this API is quite likely to do the wrong thing. A real
browser would need to pick and choose which downloads it wants to remove
based on whether the downloads are currently in progress or not -- which
is why Chrome was not using this API.

As a side-effect of removing the API, we can also remove the
Download.ClearAllSize UMA metric.

BUG=none

Review-Url: https://codereview.chromium.org/2593183002
Cr-Commit-Position: refs/heads/master@{#441769}
Committed: https://chromium.googlesource.com/chromium/src/+/6381bd4e0fb31b67ece9742b54e0f1496b45d4d6

[asanka, 2016-12-21 21:03:49]

The CQ bit was checked by asanka@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-12-21 21:04:32]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[asanka, 2016-12-21 21:05:38]

Description was changed from

==========
[downloads] Remove DownloadManager::RemoveAllDownloads.

This API was only being used by tests and most call sites were using it
incorrectly. Calling RemoveAllDownloads() immediately after creating a
DownloadManager is guaranteed to do nothing. Any new or persisted
downloads are added by some other entity asynchronously long after the
the DownloadManager has been created. In Chrome a DownloadManager starts
out empty until the downloads history DB is succuessfully queried.

Fortunately none of the tests relied on RemoveAllDownloads() doing
anything.

As a side-effect of removing the API, we can also remove the
Download.ClearAllSize UMA metric.

BUG=none
==========

to

==========
[downloads] Remove DownloadManager::RemoveAllDownloads.

This API was only being used by tests and most call sites were using it
incorrectly. Calling RemoveAllDownloads() immediately after creating a
DownloadManager is guaranteed to do nothing. Any new or persisted
downloads are added by some other entity asynchronously long after the
the DownloadManager has been created. In Chrome a DownloadManager starts
out empty until the downloads history DB is succuessfully queried.

In addition, this API is quite likely to do the wrong thing. A real
browser would need to pick and choose which downloads it wants to remove
based on whether the downloads are currently in progress or not -- which
is why Chrome was not using this API.

As a side-effect of removing the API, we can also remove the
Download.ClearAllSize UMA metric.

BUG=none
==========

[asanka, 2016-12-21 21:06:02]

asanka@chromium.org changed reviewers:
+ asvitkine@chromium.org, clamy@chromium.org, dtrainor@chromium.org

[asanka, 2016-12-21 21:06:43]

asvitkine:
  /histograms/

clamy:
  /content/public/

dtrainor:
  /download/

Thanks!

[commit-bot: I haz the power, 2016-12-21 22:06:01]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-12-21 22:06:02]

Dry run: Try jobs failed on following builders:
  linux_chromium_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  win_chromium_rel_ng on master.tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_...)

[clamy, 2016-12-22 16:08:36]

Thanks! content/public lgtm.

[asanka, 2016-12-22 16:18:25]

The CQ bit was checked by asanka@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-12-22 16:18:38]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-12-22 17:20:24]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-12-22 17:20:25]

Dry run: This issue passed the CQ dry run.

[David Trainor- moved to gerrit, 2017-01-03 19:46:50]

*/download lgtm

[Alexei Svitkine (slow), 2017-01-05 19:08:47]

lgtm

[asanka, 2017-01-05 20:39:54]

Thanks everyone!

[asanka, 2017-01-05 20:40:00]

The CQ bit was checked by asanka@chromium.org

[asanka, 2017-01-05 20:40:01]

The patchset sent to the CQ was uploaded after l-g-t-m from clamy@chromium.org
Link to the patchset: https://codereview.chromium.org/2593183002/#ps20001
(title: "Fix SavePageBrowsertest")

[commit-bot: I haz the power, 2017-01-05 20:40:47]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-01-05 20:50:55]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-01-05 20:50:56]

Try jobs failed on following builders:
  chromium_presubmit on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/chromium_presub...)

[asanka, 2017-01-05 21:06:29]

asanka@chromium.org changed reviewers:
+ jialiul@chromium.org, rdevlin.cronin@chromium.org

[asanka, 2017-01-05 21:07:49]

+jialiul: Could you give an owners' review for chrome/browser/safe_browsing ?

+rdevlin.cronin: Could you give an owner's review for chrome/browser/extensions
?

In both cases, I'm removing a no-op call to
DownloadManager::RemoveAllDownloads(). The CL description should clarify what's
going on.

[Jialiu Lin, 2017-01-05 21:09:54]

lgtm

[Devlin, 2017-01-05 21:17:47]

extensions lgtm

[asanka, 2017-01-05 21:49:38]

Thanks!

[asanka, 2017-01-05 21:49:42]

The CQ bit was checked by asanka@chromium.org

[commit-bot: I haz the power, 2017-01-05 21:50:26]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-01-05 22:08:41]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1483652982655580,
"parent_rev": "cb5e4457d0cef43f5a3676ee30139fe9be28eaa2", "commit_rev":
"6381bd4e0fb31b67ece9742b54e0f1496b45d4d6"}

[commit-bot: I haz the power, 2017-01-05 22:09:11]

Description was changed from

==========
[downloads] Remove DownloadManager::RemoveAllDownloads.

This API was only being used by tests and most call sites were using it
incorrectly. Calling RemoveAllDownloads() immediately after creating a
DownloadManager is guaranteed to do nothing. Any new or persisted
downloads are added by some other entity asynchronously long after the
the DownloadManager has been created. In Chrome a DownloadManager starts
out empty until the downloads history DB is succuessfully queried.

In addition, this API is quite likely to do the wrong thing. A real
browser would need to pick and choose which downloads it wants to remove
based on whether the downloads are currently in progress or not -- which
is why Chrome was not using this API.

As a side-effect of removing the API, we can also remove the
Download.ClearAllSize UMA metric.

BUG=none
==========

to

==========
[downloads] Remove DownloadManager::RemoveAllDownloads.

This API was only being used by tests and most call sites were using it
incorrectly. Calling RemoveAllDownloads() immediately after creating a
DownloadManager is guaranteed to do nothing. Any new or persisted
downloads are added by some other entity asynchronously long after the
the DownloadManager has been created. In Chrome a DownloadManager starts
out empty until the downloads history DB is succuessfully queried.

In addition, this API is quite likely to do the wrong thing. A real
browser would need to pick and choose which downloads it wants to remove
based on whether the downloads are currently in progress or not -- which
is why Chrome was not using this API.

As a side-effect of removing the API, we can also remove the
Download.ClearAllSize UMA metric.

BUG=none

Review-Url: https://codereview.chromium.org/2593183002
Cr-Commit-Position: refs/heads/master@{#441769}
Committed:
https://chromium.googlesource.com/chromium/src/+/6381bd4e0fb31b67ece9742b54e0...
==========

[commit-bot: I haz the power, 2017-01-05 22:09:12]

Committed patchset #2 (id:20001) as
https://chromium.googlesource.com/chromium/src/+/6381bd4e0fb31b67ece9742b54e0...