Uma stats for Data Saver prompt

Uma stats for Data Saver prompt

BUG=475194
Collects UMA stats for
(i) how  many times the Data Saver prompt (notification) is shown, and
(ii) how many times the Data Saver prompt is clicked on.

Committed: https://crrev.com/d59a713c17b430a73695e1104139c9d396cc418b
Cr-Commit-Position: refs/heads/master@{#327490}

[Greg Levin, 2015-04-28 15:25:38]

glevin@chromium.org changed reviewers:
+ jwd@chromium.org, stevenjb@chromium.org

[Greg Levin, 2015-04-28 15:25:39]

stevenjb: data_promo_notification.cc
jwd: actions.xml

Please have a look!

[jwd, 2015-04-28 18:10:45]

Hey, I don't have a problem with these being logged as actions, but many of the
data analysis tools are geared towards histograms. We actually currently have
very little support for analyzing actions data. You may wish to implement these
as histograms as well.

[stevenjb, 2015-04-28 23:03:43]

RecordAction is what we use for pretty much all UI events. We are generally only
interested in things like how many / what percentage of users are performing an
action.

LGTM

[jwd, 2015-04-29 14:17:34]

lgtm

[Greg Levin, 2015-04-29 14:49:35]

The CQ bit was checked by glevin@chromium.org

[commit-bot: I haz the power, 2015-04-29 14:49:45]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1106173003/1

[commit-bot: I haz the power, 2015-04-29 15:17:51]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-29 15:18:43]

Patchset 1 (id:??) landed as
https://crrev.com/d59a713c17b430a73695e1104139c9d396cc418b
Cr-Commit-Position: refs/heads/master@{#327490}