For #5694 & #6054: Allows users to change toolbar position

[sblatz]

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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

[codecov-io]

Codecov Report

Merging #6608 into master will decrease coverage by 0.09%.
The diff coverage is 6.17%.

@@             Coverage Diff             @@
##             master    #6608     +/-   ##
===========================================
- Coverage     17.33%   17.24%   -0.1%     
- Complexity      390      391      +1     
===========================================
  Files           280      281      +1     
  Lines         11173    11274    +101     
  Branches       1567     1592     +25     
===========================================
+ Hits           1937     1944      +7     
- Misses         9082     9175     +93     
- Partials        154      155      +1

Impacted Files	Coverage Δ	Complexity Δ
...lla/fenix/customtabs/ExternalAppBrowserFragment.kt	0% <ø> (ø)	0 <0> (ø)	⬇️
...mozilla/fenix/browser/BrowserToolbarTopBehavior.kt	0% <0%> (ø)	0 <0> (ø)	⬇️
...ava/org/mozilla/fenix/settings/SettingsFragment.kt	0% <0%> (ø)	0 <0> (ø)	⬇️
...lla/fenix/components/toolbar/BrowserToolbarView.kt	0% <0%> (ø)	0 <0> (ø)	⬇️
...va/org/mozilla/fenix/search/toolbar/ToolbarView.kt	0% <0%> (ø)	0 <0> (ø)	⬇️
...a/org/mozilla/fenix/browser/BaseBrowserFragment.kt	0% <0%> (ø)	0 <0> (ø)	⬇️
...lla/fenix/components/toolbar/DefaultToolbarMenu.kt	0% <0%> (ø)	0 <0> (ø)	⬇️
...va/org/mozilla/fenix/components/metrics/Metrics.kt	20.41% <0%> (-0.18%)	0 <0> (ø)
.../java/org/mozilla/fenix/browser/BrowserFragment.kt	0% <0%> (ø)	0 <0> (ø)	⬇️
.../mozilla/fenix/settings/ToolbarSettingsFragment.kt	0% <0%> (ø)	0 <0> (?)
... and 12 more

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[sblatz]

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 a top toolbar.
• How many users are currently using top vs bottom toolbar (core metric ping)

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?

• If more than 20% of users choose top nav bar (without surfacing this option during onboarding) then we will investigate (through user research or otherwise) whether we need to consider changing the default.

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, this is a new feature and there is no telemetry surrounding which selection users make for their toolbar position.

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.

[hiikezoe]

This looks pretty odd to me. This setVerticalClipping API ends up calling setFixedBottomOffset in GeckoView, the function does just set a margin for position:fixed elements at bottom of viewport. As far as I can tell, we need at least one new API make the top toolbar dynamic properly, the API would be a function to set an offset of the root viewport (i.e. not only for position:fixed elements).

CCing @pocmo and @snorp.

[pocmo]

Yes, for the top toolbar this should not be called at all. And I think @sblatz decided to not use this behavior implementation for the top toolbar, right? Afaik this was never really used in Fenix.

[ekager]

Could we make sure we're dealing with the snackbar anchoring correctly in browser fragments?

Maybe add a new function that gets the anchor by checking the status like
if (settings().shouldUseBottomToolbar) (toolbar.view) else null

[severinrudie]

I'd like to hear from UX on the home toolbar position, but from an engineering perspective I think this is looking really good. There are a few things that can be cleaned up before we merge though.

[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