For #18854: Add metrics for home screen being displayed.

[mcarare]

Pull Request checklist

• Tests: This PR includes thorough tests or an explanation of why it does not
• Screenshots: This PR includes screenshots or GIFs of the changes made or an explanation of why it does not
• Accessibility: The code in this PR follows accessibility best practices or does not include any user facing features. In addition, it includes a screenshot of a successful accessibility scan to ensure no new defects are added to the product.

To download an APK when reviewing a PR:

1. click on Show All Checks,
2. click Details next to "Taskcluster (pull_request)" after it appears and then finishes with a green checkmark,
3. click on the "Fenix - assemble" task, then click "Run Artifacts".
4. the APK links should be on the left side of the screen, named for each CPU architecture

[mcarare]

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?
   This will help us understand user interaction with the home screen, how many times components inside this screen are being visualized by users.

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:
   Determine how many people interact with this screen related to the number of times it is displayed.

3. What alternative methods did you consider to answer these questions? Why were they not sufficient?
   No other alternative.

4. Can current instrumentation answer these questions?
   No.

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.

Measurement Description	Data Collection Category	Tracking Bug #
Home Screen has been displayed	category 2 - interaction data	#18854

6. Please provide a link to the documentation for this data collection which describes the ultimate data set in a public, complete, and accurate way.
   https://github.com/mozilla-mobile/fenix/blob/master/docs/metrics.md

7. How long will this data be collected? Choose one of the following:
   2021-10-01

8. What populations will you measure?
   All channels.

9. If this data collection is default on, what is the opt-out mechanism for users?
   Default Glean SDK opt-out mechanism.

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

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

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

[mcarare]

tagging @tdsmith for data review.
Note: I was not sure if the event should be classified as interaction or technical being just a normal display of a screen, but I chose to classify it as interaction as it is displayed as a result of a user intent.

[codecov-io]

Codecov Report

Merging #19025 (b0a47ce) into master (1128f92) will decrease coverage by 0.02%.
The diff coverage is 0.00%.

@@             Coverage Diff              @@
##             master   #19025      +/-   ##
============================================
- Coverage     33.67%   33.64%   -0.03%     
+ Complexity     1545     1544       -1     
============================================
  Files           532      532              
  Lines         21591    21595       +4     
  Branches       3218     3220       +2     
============================================
- Hits           7270     7265       -5     
- Misses        13433    13446      +13     
+ Partials        888      884       -4     

Impacted Files	Coverage Δ	Complexity Δ
...java/org/mozilla/fenix/components/metrics/Event.kt	39.43% <0.00%> (-0.12%)	0.00 <0.00> (ø)
...la/fenix/components/metrics/GleanMetricsService.kt	21.55% <0.00%> (-0.08%)	5.00 <0.00> (ø)
...c/main/java/org/mozilla/fenix/home/HomeFragment.kt	2.42% <0.00%> (-1.02%)	5.00 <0.00> (-1.00)

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[Amejia481]

✅

[mergify]

This pull request has conflicts when rebasing. Could you fix it @mcarare? 🙏

[tdsmith]

data-review+, thanks!

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, in the probe definition files and the Glean probe dictionary.

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

Yes, the Firefox telemetry opt-out.

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

n/a

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

Cat 2, interaction.

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?

The team is responsible for renewing as needed.

9. Does the data collection use a third-party collection tool?

No.

[mcarare]

@tdsmith Thank you!

[mcarare]

test-debug seems stuck. Closing and reopening.