Add a BeginMainFrame fallback to MainThreadEventQueue.

Add a BeginMainFrame fallback to MainThreadEventQueue.

I believe we aren't always getting the begin main frame signal leading
to an increase in hung renderers when rAF mouse aligned input is
enabled. Test my theory by adding a timer that fires after a
significantly long time (5s) if we are waiting for a signal but
haven't received it.

BUG=703344
Review-Url: https://codereview.chromium.org/2846333002
Cr-Commit-Position: refs/heads/master@{#468464}
Committed: https://chromium.googlesource.com/chromium/src/+/53bb807ea69fe34161a9cd85dfa0a20a7bf14fea

[dtapuska, 2017-04-28 20:43:07]

dtapuska@chromium.org changed reviewers:
+ isherman@chromium.org, tdresser@chromium.org

[Ilya Sherman, 2017-04-28 20:54:11]

Is the added histogram measuring an exceptional situation that should never be
reached?  If not, how do you plan to contextualize the numbers that you see? 
I'd recommend building in a baseline to the histogram, by recording the opposite
case in the 'false' bucket.

[dtapuska, 2017-04-28 21:00:45]

On 2017/04/28 20:54:11, Ilya Sherman wrote:
> Is the added histogram measuring an exceptional situation that should never be
> reached?  If not, how do you plan to contextualize the numbers that you see? 
> I'd recommend building in a baseline to the histogram, by recording the
opposite
> case in the 'false' bucket.

Yes the histogram is measuring a situation that should never be reached. I
believe that we are hitting it though and I'd like to understand if we are. I
agree there is no denominator here really. But we don't need to know what
percentage we are hitting just that we are. And if we are that isn't good.

[Ilya Sherman, 2017-04-28 21:02:22]

On 2017/04/28 21:00:45, dtapuska wrote:
> On 2017/04/28 20:54:11, Ilya Sherman wrote:
> > Is the added histogram measuring an exceptional situation that should never
be
> > reached?  If not, how do you plan to contextualize the numbers that you see?

> > I'd recommend building in a baseline to the histogram, by recording the
> opposite
> > case in the 'false' bucket.
> 
> Yes the histogram is measuring a situation that should never be reached. I
> believe that we are hitting it though and I'd like to understand if we are. I
> agree there is no denominator here really. But we don't need to know what
> percentage we are hitting just that we are. And if we are that isn't good.

Okay, thanks for the explanation.  BooleanHit does make sense in that case. 
LGTM.

[tdresser, 2017-05-01 12:40:44]

LGTM.

Should we have a comment indicating a removal milestone for this?

Adding a DCHECK as well might be useful, in case a Chrome engineer is able to
find a repro.

https://codereview.chromium.org/2846333002/diff/1/tools/metrics/histograms/hi...
File tools/metrics/histograms/histograms.xml (right):

https://codereview.chromium.org/2846333002/diff/1/tools/metrics/histograms/hi...
tools/metrics/histograms/histograms.xml:16992: +    Team:
input-dev@chromium.org.
Thanks for adding the team annotation!

[dtapuska, 2017-05-01 12:53:27]

On 2017/05/01 12:40:44, tdresser wrote:
> LGTM.
> 
> Should we have a comment indicating a removal milestone for this?
> 
> Adding a DCHECK as well might be useful, in case a Chrome engineer is able to
> find a repro.
> 
>
https://codereview.chromium.org/2846333002/diff/1/tools/metrics/histograms/hi...
> File tools/metrics/histograms/histograms.xml (right):
> 
>
https://codereview.chromium.org/2846333002/diff/1/tools/metrics/histograms/hi...
> tools/metrics/histograms/histograms.xml:16992: +    Team:
> mailto:input-dev@chromium.org.
> Thanks for adding the team annotation!

dchecks for timers are problematic due to using a debugger so I'd prefer not
hamper people's ability to debug.

[dtapuska, 2017-05-01 12:53:40]

The CQ bit was checked by dtapuska@chromium.org

[commit-bot: I haz the power, 2017-05-01 12:53:55]

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, 2017-05-01 13:19:35]

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

[commit-bot: I haz the power, 2017-05-01 13:19:36]

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

[Ilya Sherman, 2017-05-01 18:00:49]

histograms.xml lgtm

[dtapuska, 2017-05-01 19:29:22]

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

[commit-bot: I haz the power, 2017-05-01 19:29:54]

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, 2017-05-01 21:38:04]

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

[commit-bot: I haz the power, 2017-05-01 21:38:05]

Dry run: This issue passed the CQ dry run.

[dtapuska, 2017-05-01 22:38:42]

The CQ bit was checked by dtapuska@chromium.org

[dtapuska, 2017-05-01 22:38:43]

The patchset sent to the CQ was uploaded after l-g-t-m from
isherman@chromium.org, tdresser@chromium.org
Link to the patchset: https://codereview.chromium.org/2846333002/#ps20001
(title: "Fix tests")

[commit-bot: I haz the power, 2017-05-01 22:39:24]

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, 2017-05-01 22:45:29]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1493678322510620,
"parent_rev": "c6376a644a8db12cb1deebe497db1f390be8d11e", "commit_rev":
"88579e6d92f829dc79dd5a64aa24ad3f0d078d2e"}

[commit-bot: I haz the power, 2017-05-01 22:45:47]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1493678322510620,
"parent_rev": "cbe6631e139403fbf638883cfc4383f851c81d77", "commit_rev":
"53bb807ea69fe34161a9cd85dfa0a20a7bf14fea"}

[commit-bot: I haz the power, 2017-05-01 22:45:59]

Description was changed from

==========
Add a BeginMainFrame fallback to MainThreadEventQueue.

I believe we aren't always getting the begin main frame signal leading
to an increase in hung renderers when rAF mouse aligned input is
enabled. Test my theory by adding a timer that fires after a
significantly long time (5s) if we are waiting for a signal but
haven't received it.

BUG=703344
==========

to

==========
Add a BeginMainFrame fallback to MainThreadEventQueue.

I believe we aren't always getting the begin main frame signal leading
to an increase in hung renderers when rAF mouse aligned input is
enabled. Test my theory by adding a timer that fires after a
significantly long time (5s) if we are waiting for a signal but
haven't received it.

BUG=703344

Review-Url: https://codereview.chromium.org/2846333002
Cr-Commit-Position: refs/heads/master@{#468464}
Committed:
https://chromium.googlesource.com/chromium/src/+/53bb807ea69fe34161a9cd85dfa0...
==========

[commit-bot: I haz the power, 2017-05-01 22:46:01]

Committed patchset #2 (id:20001) as
https://chromium.googlesource.com/chromium/src/+/53bb807ea69fe34161a9cd85dfa0...