predictors: Add subresources count and prefetching duration histograms.

predictors: Add subresources count and prefetching duration histograms.

This CL adds two more histograms for ResourcePrefetchPredictor trial.
ResourcePrefetchPredictor.LearningCount shows how many useful subresources are
contained in the database during prefetch predictor learning.
ResourcePrefetchPredictor.PrefetchingDuration allows to estimate time window
available for prefetching.

BUG=680049
Review-Url: https://codereview.chromium.org/2683633004
Cr-Commit-Position: refs/heads/master@{#449331}
Committed: https://chromium.googlesource.com/chromium/src/+/c374785047c1c350a944dc1836cc254c27cc0329

[alexilin, 2017-02-08 10:31:58]

alexilin@chromium.org changed reviewers:
+ asvitkine@chromium.org, lizeb@chromium.org

[alexilin, 2017-02-08 10:31:59]

asvitkine: please review histograms.xml, thanks!
lizeb: everything, as usual

[alexilin, 2017-02-08 15:27:48]

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

[commit-bot: I haz the power, 2017-02-08 15:28:12]

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, 2017-02-08 16:25:30]

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

[commit-bot: I haz the power, 2017-02-08 16:25:31]

Dry run: This issue passed the CQ dry run.

[Alexei Svitkine (slow), 2017-02-08 16:32:32]

lgtm

[Benoit L, 2017-02-09 02:24:52]

lgtm, but let's see how to coordinate with
https://codereview.chromium.org/2688633002/, as some code may be duplicated
here.

https://codereview.chromium.org/2683633004/diff/20001/chrome/browser/predicto...
File chrome/browser/predictors/resource_prefetch_predictor.h (right):

https://codereview.chromium.org/2683633004/diff/20001/chrome/browser/predicto...
chrome/browser/predictors/resource_prefetch_predictor.h:292: //
inflight_navigations_ and inflight_prefetchings_.
nit: s/prefetchings/prefetches/

https://codereview.chromium.org/2683633004/diff/20001/chrome/browser/predicto...
chrome/browser/predictors/resource_prefetch_predictor.h:373: std::map<GURL,
base::TimeTicks> inflight_prefetchings_;
nit: ditto, for the renaming.

https://codereview.chromium.org/2683633004/diff/20001/chrome/browser/predicto...
File chrome/browser/predictors/resource_prefetch_predictor_unittest.cc (right):

https://codereview.chromium.org/2683633004/diff/20001/chrome/browser/predicto...
chrome/browser/predictors/resource_prefetch_predictor_unittest.cc:1609: //
Prefetching duration for an url without resoruces in the database
nit: resources

[alexilin, 2017-02-09 15:50:19]

I've checked your CL, there is no duplication. 
We can't merge inflight_prefetches and prefetcher_stats because prefetcher_stats
exist only if prefetcher is enabled but inflight_prefetches don't require it. +
theirs entries have different lifetime.

https://codereview.chromium.org/2683633004/diff/20001/chrome/browser/predicto...
File chrome/browser/predictors/resource_prefetch_predictor.h (right):

https://codereview.chromium.org/2683633004/diff/20001/chrome/browser/predicto...
chrome/browser/predictors/resource_prefetch_predictor.h:292: //
inflight_navigations_ and inflight_prefetchings_.
On 2017/02/09 02:24:52, Benoit L wrote:
> nit: s/prefetchings/prefetches/

Done.

https://codereview.chromium.org/2683633004/diff/20001/chrome/browser/predicto...
chrome/browser/predictors/resource_prefetch_predictor.h:373: std::map<GURL,
base::TimeTicks> inflight_prefetchings_;
On 2017/02/09 02:24:52, Benoit L wrote:
> nit: ditto, for the renaming.

Done.

https://codereview.chromium.org/2683633004/diff/20001/chrome/browser/predicto...
File chrome/browser/predictors/resource_prefetch_predictor_unittest.cc (right):

https://codereview.chromium.org/2683633004/diff/20001/chrome/browser/predicto...
chrome/browser/predictors/resource_prefetch_predictor_unittest.cc:1609: //
Prefetching duration for an url without resoruces in the database
On 2017/02/09 02:24:52, Benoit L wrote:
> nit: resources

Done.

[alexilin, 2017-02-09 15:50:43]

The CQ bit was checked by alexilin@chromium.org

[alexilin, 2017-02-09 15:50:44]

The patchset sent to the CQ was uploaded after l-g-t-m from lizeb@chromium.org,
asvitkine@chromium.org
Link to the patchset: https://codereview.chromium.org/2683633004/#ps40001
(title: "Nits.")

[commit-bot: I haz the power, 2017-02-09 15:51:18]

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, 2017-02-09 17:18:20]

CQ is committing da patch.

Bot data: {"patchset_id": 40001, "attempt_start_ts": 1486655443827660,
"parent_rev": "311566f4127c78cc085c99e52833592c673fed01", "commit_rev":
"c374785047c1c350a944dc1836cc254c27cc0329"}

[commit-bot: I haz the power, 2017-02-09 17:18:56]

Description was changed from

==========
predictors: Add subresources count and prefetching duration histograms.

This CL adds two more histograms for ResourcePrefetchPredictor trial.
ResourcePrefetchPredictor.LearningCount shows how many useful subresources are
contained in the database during prefetch predictor learning.
ResourcePrefetchPredictor.PrefetchingDuration allows to estimate time window
available for prefetching.

BUG=680049
==========

to

==========
predictors: Add subresources count and prefetching duration histograms.

This CL adds two more histograms for ResourcePrefetchPredictor trial.
ResourcePrefetchPredictor.LearningCount shows how many useful subresources are
contained in the database during prefetch predictor learning.
ResourcePrefetchPredictor.PrefetchingDuration allows to estimate time window
available for prefetching.

BUG=680049

Review-Url: https://codereview.chromium.org/2683633004
Cr-Commit-Position: refs/heads/master@{#449331}
Committed:
https://chromium.googlesource.com/chromium/src/+/c374785047c1c350a944dc1836cc...
==========

[commit-bot: I haz the power, 2017-02-09 17:18:57]

Committed patchset #3 (id:40001) as
https://chromium.googlesource.com/chromium/src/+/c374785047c1c350a944dc1836cc...