Add a histogram to log the size of an UMA upload.

Add a histogram to log the size of an UMA upload.

This is better than the existing pair of histograms
UMA.ProtoCompressionRatio and UMA.ProtoGzippedKBSaved
which require manual calculation to get at the approx.
value.

BUG=409179
Committed: https://crrev.com/d80ebf6cfa81d71cc24198e5ec5b62d0c26063dc
Cr-Commit-Position: refs/heads/master@{#293011}

[Alexei Svitkine (slow), 2014-08-29 21:33:34]

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

[Ilya Sherman, 2014-08-30 01:23:23]

https://codereview.chromium.org/523153002/diff/1/components/metrics/metrics_s...
File components/metrics/metrics_service.cc (right):

https://codereview.chromium.org/523153002/diff/1/components/metrics/metrics_s...
components/metrics/metrics_service.cc:1030:
UMA_HISTOGRAM_COUNTS_10000("UMA.LogSize", log_size / 1024);
Hmm, why not record this for all logs when sending the upload, rather than only
for successful logs after the upload response is received?  I guess it's not
obvious to me which is more useful; but the filtering by success does seem like
it could limit visibility into any potential problems with discarding large
logs.

[Alexei Svitkine (slow), 2014-09-02 14:50:37]

https://codereview.chromium.org/523153002/diff/1/components/metrics/metrics_s...
File components/metrics/metrics_service.cc (right):

https://codereview.chromium.org/523153002/diff/1/components/metrics/metrics_s...
components/metrics/metrics_service.cc:1030:
UMA_HISTOGRAM_COUNTS_10000("UMA.LogSize", log_size / 1024);
On 2014/08/30 01:23:23, Ilya Sherman wrote:
> Hmm, why not record this for all logs when sending the upload, rather than
only
> for successful logs after the upload response is received?  I guess it's not
> obvious to me which is more useful; but the filtering by success does seem
like
> it could limit visibility into any potential problems with discarding large
> logs.

I want to use this histogram to capture how much data is sent up to Google
servers (and do so client-side so that e.g. I can see the effect of experiments
on this - e.g. playing with upload frequency), so I'm only interested in
successes (to avoid e.g. double counting on re-transmissions).

[Ilya Sherman, 2014-09-02 20:13:45]

Fair enough; LGTM.  Thanks, Alexei.

https://codereview.chromium.org/523153002/diff/1/tools/metrics/histograms/his...
File tools/metrics/histograms/histograms.xml (right):

https://codereview.chromium.org/523153002/diff/1/tools/metrics/histograms/his...
tools/metrics/histograms/histograms.xml:34587: +<histogram name="UMA.LogSize"
units="KB">
Optional nit: Perhaps lets name this to make it dead clear that this only deals
with successful uploads, e.g. "UMA.LogSize.OnSuccess[fulUpload]"?

[Alexei Svitkine (slow), 2014-09-02 21:10:45]

https://codereview.chromium.org/523153002/diff/1/tools/metrics/histograms/his...
File tools/metrics/histograms/histograms.xml (right):

https://codereview.chromium.org/523153002/diff/1/tools/metrics/histograms/his...
tools/metrics/histograms/histograms.xml:34587: +<histogram name="UMA.LogSize"
units="KB">
On 2014/09/02 20:13:45, Ilya Sherman wrote:
> Optional nit: Perhaps lets name this to make it dead clear that this only
deals
> with successful uploads, e.g. "UMA.LogSize.OnSuccess[fulUpload]"?

Done.

[Alexei Svitkine (slow), 2014-09-02 21:10:49]

The CQ bit was checked by asvitkine@chromium.org

[commit-bot: I haz the power, 2014-09-02 21:11:49]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/asvitkine@chromium.org/523153002/20001

[commit-bot: I haz the power, 2014-09-02 22:30:14]

Committed patchset #2 (id:20001) as 714888b389ed6b20c47217966218ed9c79751eac

[commit-bot: I haz the power, 2014-09-10 03:21:23]

Patchset 2 (id:??) landed as
https://crrev.com/d80ebf6cfa81d71cc24198e5ec5b62d0c26063dc
Cr-Commit-Position: refs/heads/master@{#293011}