Integrate with remote config to determine if autofill is on by default

[CDRussell]

Task/Issue URL: https://app.asana.com/0/0/1205811927559467/f

Description

Integrates with remote config to determine if Autofill should be enabled by default, for new users only.

• New remote config Autofill subfeature onByDefault will be introduced and incrementally rolled out
• For now, a user will get Autofill enabled by default only if the incremental rollout enables it for a brand new user (installed today). If on the first day the incremental rollout determines a user:
  • can have it enabled by default, it'll be enabled. And this will be recorded locally so we know they had it enabled by default.
  • can not have it enabled by default, it won't be enabled by default
  • Even if it later becomes available to them through the incremental rollout then they still won't have it on by default if that happens after the initial install day. (i.e., they can have the subfeature onByDefault return true but they still won't get it enabled by default)
• If we determine a user can have it enabled by default today, we'll save this setting so that it's on by default tomorrow and thereafter (even when they're not a new user)

Steps to test this PR

Need to use play builds to properly test this, as internal builds default to enabled by default.

To make tester simpler, would recommend:

• changing the following in PrivacyConfigPersister. Change line 63 to be val previousVersion = 0L to bypass version checks from the downloaded config
• hardcoding URL in PrivacyConfigService as needed for the tests below

When remote config new field not yet available

• Fresh install play build and let it consume production remote config
• Visit Logins and verify it is disabled by default

When remote config new field available but not enabled for current user

• Hardcode privacy config to return onByDefault enabled but rolled out to nobody (example)
• Fresh install play build and let it consume remote config
• Visit Logins and verify it is disabled by default

When remote config available to a user on install day

• Hardcode privacy config to return onByDefault enabled for everybody (example)
• Fresh install play build and let it consume remote config
• Visit Logins and verify it is enabled by default
• Set device date forward some days (tip: adb shell am start -a android.settings.DATE_SETTINGS)
• Visit Logins and verify it is still enabled by default
• Disable it, leave Login settings and return. Verify it remains disabled, respecting the manual selection

When remote config available to a user but not on install day

• Hardcode privacy config to return onByDefault enabled but rolled out to nobody (example)
• Fresh install play build and let it consume remote config
• Visit Logins and verify it is disabled by default
• Set device date forward (tip: adb shell am start -a android.settings.DATE_SETTINGS)
• Hardcode privacy config to return onByDefault enabled for everybody (example) (might have to do this with a proxy or hardcode JSON if date causes SSL issues). Kill and relaunch app and let it consume remote config.
• Visit Logins and verify it is still disabled by default

[CDRussell]

Current dependencies on/for this PR:

• develop
  • PR Preparation for Autofill enabled by default #3695
    • PR Update autofill dialog copy, changing "logins" to "passwords" #3867
    • PR Fix bug: should use sdkInt as the property to compare #3865
    • PR Update copy for autofill dialogs, switching from login to password #3844
    • PR Suppress system AutofillService save prompts to prevent it overlapping in-browser save prompts #3840
    • PR Updated autofill dialog designs #3807
    • PR Apply max-width constraints to autofill dialogs' contents #3773
    • PR Integrate with remote config to determine if autofill is on by default #3760 👈
      • PR Add autofill default state param to key autofill pixels #3761
    • PR Update button copy for 'not now' buttons #3711
    • PR Reduce autofill decline count threshold before prompting to disable #3703
    • PR De-duplicate login suggestions offered to a user for autofilling credentials #3702
      • PR Add dev settings for quickly adding Logins for testing (including duplicates) #3734
    • PR Update autofill copy #3696

This stack of pull requests is managed by Graphite.

[aitorvs]

lgtm and PR test steps work as expected