For #5705 - Adds telemetry for media state

[gabrielluong]

This fixes #5705. We pick up the Facts emitted from the Media component that are documented in https://github.com/mozilla-mobile/android-components/tree/master/components/feature/media#facts.

Action	Item	Description
PLAY	state	Media started playing.
PAUSE	state	Media playback was paused.
STOP	state	Media playback has ended.

---

Pull Request checklist

• Quality: This PR builds and passes detekt/ktlint checks (A pre-push hook is recommended)
• 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

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

[gabrielluong]

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 the browser is used to play media

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?

• This will help us prioritize bugs with media tickets (depending on how popular the feature is)

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

• We currently record interacting with the play/pause button on the tab itself and media notification, but nothing tracks the media usage state.

4. Can current instrumentation answer these questions?

• Currently there are no events to track this.

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 03/01/2020

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 #6463 into master will decrease coverage by 0.02%.
The diff coverage is 0%.

@@             Coverage Diff              @@
##             master    #6463      +/-   ##
============================================
- Coverage      16.8%   16.77%   -0.03%     
  Complexity      349      349              
============================================
  Files           271      271              
  Lines         10635    10650      +15     
  Branches       1478     1483       +5     
============================================
  Hits           1787     1787              
- Misses         8701     8716      +15     
  Partials        147      147

Impacted Files	Coverage Δ	Complexity Δ
...la/fenix/components/metrics/GleanMetricsService.kt	7.71% <0%> (-0.17%)	3 <0> (ø)
...va/org/mozilla/fenix/components/metrics/Metrics.kt	21.97% <0%> (-0.93%)	0 <0> (ø)

---

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 cc31802...d93bf17. Read the comment docs.

[gabrielluong]

CC @boek / @liuche for data review

[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, in metrics.yaml and the generated metrics.md

2. Is there a control mechanism that allows the user to turn the data collection on and off? (Note, for data collection not needed for security purposes, Mozilla provides such a control mechanism) Provide details as to the control mechanism available.

Controlled by Fenix 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, media playback 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? (Yes/No) (If yes, set a todo reminder or file a bug if appropriate)**

Has expiry

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

No