Add concurrency check to HistogramSnapshotManager.

Add concurrency check to HistogramSnapshotManager.

Using ThreadChecker causes problems when outside code is doing its
own synchronization between multiple calling threads so remove that
and add an atomic to do a run-time concurrency CHECK.  This will
likely be removed in the future once it's well assured that concurrent
access is not the cause of the corrupted data structures.

Also, make known_histograms_ member "const" as it should have been from
the beginning.

BUG=719448, 600717
Review-Url: https://codereview.chromium.org/2871663003
Cr-Commit-Position: refs/heads/master@{#470178}
Committed: https://chromium.googlesource.com/chromium/src/+/947514553066c623a85712d05c3a01bd1bcbbffc

[bcwhite, 2017-05-08 18:15:22]

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

[commit-bot: I haz the power, 2017-05-08 18:16:36]

Dry run: CQ is trying da patch.

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

[bcwhite, 2017-05-08 18:48:05]

bcwhite@chromium.org changed reviewers:
+ asvitkine@chromium.org

[Alexei Svitkine (slow), 2017-05-08 18:51:09]

lgtm

https://codereview.chromium.org/2871663003/diff/1/base/metrics/histogram_snap...
File base/metrics/histogram_snapshot_manager.cc (right):

https://codereview.chromium.org/2871663003/diff/1/base/metrics/histogram_snap...
base/metrics/histogram_snapshot_manager.cc:30: std::atomic<bool>* is_active_;
Nit: DISALLOW_COPY_AND_ASSIGN()

[bcwhite, 2017-05-08 19:48:36]

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

[commit-bot: I haz the power, 2017-05-08 19:49:26]

Dry run: CQ is trying da patch.

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

[bcwhite, 2017-05-08 20:06:50]

https://codereview.chromium.org/2871663003/diff/1/base/metrics/histogram_snap...
File base/metrics/histogram_snapshot_manager.cc (right):

https://codereview.chromium.org/2871663003/diff/1/base/metrics/histogram_snap...
base/metrics/histogram_snapshot_manager.cc:30: std::atomic<bool>* is_active_;
On 2017/05/08 18:51:09, Alexei Svitkine (slow) wrote:
> Nit: DISALLOW_COPY_AND_ASSIGN()

Done.

[bcwhite, 2017-05-08 20:06:56]

The CQ bit was unchecked by bcwhite@chromium.org

[bcwhite, 2017-05-08 20:07:01]

The CQ bit was checked by bcwhite@chromium.org

[bcwhite, 2017-05-08 20:07:01]

The patchset sent to the CQ was uploaded after l-g-t-m from
asvitkine@chromium.org
Link to the patchset: https://codereview.chromium.org/2871663003/#ps20001
(title: "disallow copy and assign")

[commit-bot: I haz the power, 2017-05-08 20:07:26]

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, 2017-05-09 04:01:21]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1494274021120930,
"parent_rev": "57c7bade1d0161cb8bf445a832d884331d28d6c6", "commit_rev":
"947514553066c623a85712d05c3a01bd1bcbbffc"}

[commit-bot: I haz the power, 2017-05-09 04:01:32]

Description was changed from

==========
Add concurrency check to HistogramSnapshotManager.

Using ThreadChecker causes problems when outside code is doing its
own synchronization between multiple calling threads so remove that
and add an atomic to do a run-time concurrency CHECK.  This will
likely be removed in the future once it's well assured that concurrent
access is not the cause of the corrupted data structures.

Also, make known_histograms_ member "const" as it should have been from
the beginning.

BUG=719448, 600717
==========

to

==========
Add concurrency check to HistogramSnapshotManager.

Using ThreadChecker causes problems when outside code is doing its
own synchronization between multiple calling threads so remove that
and add an atomic to do a run-time concurrency CHECK.  This will
likely be removed in the future once it's well assured that concurrent
access is not the cause of the corrupted data structures.

Also, make known_histograms_ member "const" as it should have been from
the beginning.

BUG=719448, 600717

Review-Url: https://codereview.chromium.org/2871663003
Cr-Commit-Position: refs/heads/master@{#470178}
Committed:
https://chromium.googlesource.com/chromium/src/+/947514553066c623a85712d05c3a...
==========

[commit-bot: I haz the power, 2017-05-09 04:01:33]

Committed patchset #2 (id:20001) as
https://chromium.googlesource.com/chromium/src/+/947514553066c623a85712d05c3a...