For #6577 - total_uri_count Glean telemetry

[Mugurell]

Use total_uri_count as a Glean CounterMetricType tracked in both the baseline and metrics ping.
This would also complement the changes for #4456.

Pull Request checklist

• Tests: This PR does not include tests as it only refactor specific telemetry events.
• Screenshots: This PR does not include screenshots as the changes are only for telemetry.
• Accessibility: The code in this PR does not include any user facing features.

After merge

• Milestone: Make sure issues finished by this pull request are added to the milestone of the version currently in development.

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[codecov-io]

Codecov Report

Merging #8314 into master will decrease coverage by 0.03%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##             master   #8314      +/-   ##
===========================================
- Coverage     18.53%   18.5%   -0.04%     
  Complexity      452     452              
===========================================
  Files           317     317              
  Lines         12485   12479       -6     
  Branches       1641    1641              
===========================================
- Hits           2314    2309       -5     
+ Misses         9972    9971       -1     
  Partials        199     199

Impacted Files	Coverage Δ	Complexity Δ
...la/fenix/components/metrics/GleanMetricsService.kt	7.59% <ø> (-0.26%)	3 <0> (ø)
...ava/org/mozilla/fenix/browser/UriOpenedObserver.kt	56.52% <ø> (-1.82%)	3 <0> (ø)
.../src/main/java/org/mozilla/fenix/utils/Settings.kt	73.45% <ø> (-0.35%)	28 <0> (ø)

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[boek]

Please fill out a data review request form and add it as a comment here, I'll review it right away 😁!

[Mugurell]

Request for data collection review form

All questions are mandatory. You must receive review from a data steward peer on your responses to these questions before shipping new data collection.

1. What questions will you answer with this data?
   A counter of URIs visited by the user in the current session, including page reloads.
   This does not include background page requests and URIs from embedded pages or private browsing.

2. Why does Mozilla need to answer these questions? Are there benefits for users? Do we need this information to address product or business requirements? Some example responses:
   This allows for a better assessment of the app's usage.

3. What alternative methods did you consider to answer these questions? Why were they not sufficient?
   N/A

4. Can current instrumentation answer these questions?
   This comes to improve the way we are collected data initially requested in [Telemetry] Add uri_count to ping #1301

5. List all proposed measurements and indicate the category of data collection for each measurement, using the Firefox data collection categories found on the Mozilla wiki.

Note that the data steward reviewing your request will characterize your data collection based on the highest (and most sensitive) category.

Measurement Description	Data Collection Category	Tracking Bug #
uri visits	Category 2	https://github.com//issues/1301 https://github.com//issues/4456

6. How long will this data be collected? Choose one of the following:
   This is scoped to a time-limited experiment/project until date 09-01-2020.

7. What populations will you measure?
   All release, beta, and nightly users with telemetry enabled.

8. If this data collection is default on, what is the opt-out mechanism for users?
   Users can opt of of data collection by disabling Usage and technical data from Settings -> Data collection.

9. Please provide a general description of how you will analyze this data.
   Glean / Amplitude

10. Where do you intend to share the results of your analysis?
    Only on Glean, Amplitude and with mobile teams.

11. Is there a third-party tool (i.e. not Telemetry) that you are proposing to use for this data collection?
    No.

[Dexterp37]

This looks good to me from a Glean usage point of view. Please address the nits below as well :)

[Dexterp37]

Oh, let's also wait for @sblatz to review this, since I don't own this repo :-P

[boek]

Data Review Form (to be filled by Data Stewards)

1. Is there or will there be documentation that describes the schema for the ultimate data set in a public, complete, and accurate way?
   Yes, metrics.yaml and metrics.md

2. Is there a control mechanism that allows the user to turn the data collection on and off?
   Yes, under data controls

3. If the request is for permanent data collection, is there someone who will monitor the data over time?
   Has expiry

4. Using the category system of data types on the Mozilla wiki, what collection type of data do the requested measurements fall under?
   Type 2

5. Is the data collection request for default-on or default-off?
   Default on

6. Does the instrumentation include the addition of any new identifiers (whether anonymous or otherwise; e.g., username, random IDs, etc. See the appendix for more details)?
   No

7. Is the data collection covered by the existing Firefox privacy notice?
   Yes

8. Does there need to be a check-in in the future to determine whether to renew the data?
   Has expiry

9. Does the data collection use a third-party collection tool?
   no