For #7289: Adds telemetry for selecting dark theme

[ValentinTimisica]

Pull Request checklist

• Tests: This PR does not include thorough tests.
• Screenshots: This PR does not include screenshots or GIFs.
• 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.

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

[ValentinTimisica]

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?

• How often users choose Dark Theme?

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?

• Want to know how often users choose dark mode, in order to better prioritize feature optimizations.

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

• N/A (These are baseline metrics).

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 on the found on the Mozilla wiki.

• All data is Category 2.

6. How long will this data be collected?

• Until 09/01/2020.

7. What populations will you measure?

• All release, beta, and nightly users with telemetry enabled.

8. Please provide a general description of how you will analyze this data.

• Glean / Amplitude.

9. Where do you intend to share the results of your analysis?

• Only on Glean, Amplitude and with mobile teams.

[codecov-io]

Codecov Report

Merging #7968 into master will increase coverage by 0.02%.
The diff coverage is 0%.

@@             Coverage Diff              @@
##             master    #7968      +/-   ##
============================================
+ Coverage     19.15%   19.18%   +0.02%     
+ Complexity      454      452       -2     
============================================
  Files           306      305       -1     
  Lines         11902    11853      -49     
  Branches       1603     1596       -7     
============================================
- Hits           2280     2274       -6     
+ Misses         9431     9388      -43     
  Partials        191      191

Impacted Files	Coverage Δ	Complexity Δ
...la/fenix/components/metrics/GleanMetricsService.kt	7.83% <0%> (+0.16%)	3 <0> (ø)	⬇️
...va/org/mozilla/fenix/components/metrics/Metrics.kt	21.65% <0%> (+0.25%)	0 <0> (ø)	⬇️
...n/java/org/mozilla/fenix/settings/ThemeFragment.kt	0% <0%> (ø)	0 <0> (ø)	⬇️
...ders/onboarding/OnboardingThemePickerViewHolder.kt	0% <0%> (ø)	0 <0> (ø)	⬇️
...ttings/advanced/DefaultLocaleSettingsController.kt	80% <0%> (-12.86%)	4% <0%> (-2%)
...ttings/quicksettings/QuickSettingsFragmentStore.kt	71.51% <0%> (-0.17%)	2% <0%> (ø)
...la/fenix/settings/quicksettings/WebsiteInfoView.kt	0% <0%> (ø)	0% <0%> (ø)	⬇️
...g/mozilla/fenix/settings/logins/SavedLoginsView.kt	0% <0%> (ø)	0% <0%> (ø)	⬇️
...zilla/fenix/migration/MigrationProgressActivity.kt	0% <0%> (ø)	0% <0%> (ø)	⬇️
app/src/main/java/org/mozilla/fenix/utils/Undo.kt	0% <0%> (ø)	0% <0%> (ø)	⬇️
... and 16 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 2026c60...6932e6c. Read the comment docs.

[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?
   Will check-in at expiry

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