Add WinBackPromptEvaluator to re-engage users who were previously default browser

[catalinradoiu]

Task/Issue URL:https://app.asana.com/1/137249556945/project/1211724162604201/task/1213440050991462?focus=true

Description

Introduces a "win back" prompt for users who previously set DuckDuckGo as their default browser but no longer have it set as default. Key changes include:

• Added a new WinBackPromptEvaluator that shows the browser comparison screen to eligible users (those who were once the default browser but no longer are, and haven't seen the browser comparison prompt before). This evaluator is registered as a ModalEvaluator with the highest priority (1).
• Bumped RemoteMessageModalSurfaceEvaluator priority from 1 to 2 and AdditionalDefaultBrowserPromptsImpl priority from 2 to 3 to accommodate the new evaluator's priority slot.
• Consolidated wasEverDefaultBrowser tracking logic into the defaultBrowser setter in AppInstallSharedPreferences. Setting defaultBrowser = true now automatically and permanently flips wasEverDefaultBrowser to true, removing the need for callers to set it manually. wasEverDefaultBrowser is now a read-only val.
• Exposed wasEverDefaultBrowser through the UserBrowserProperties interface and its Android implementation.

Steps to test this PR

Win Back Prompt

• Clean install the app and enable the reactivateUsers and defaultBrowserWinBackPrompt feature toggles
• From the settings set the app as default browser and resume the app
• Set another app as default browser and then resume the app
• The re-engagement prompt should be displayed

UI changes

Show the browser comparison prompt when the user unsets the app as the default browser and then resumes the app:

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Note

Medium Risk
Adds a new high-priority ModalEvaluator that can launch an activity after a delay and changes default-browser state tracking behavior; issues here could cause unexpected modal ordering or incorrect eligibility decisions but are gated by feature toggles and covered by unit tests.

Overview
Adds a new WinBackPromptEvaluator modal (priority 1) that, when feature-toggled on, shows the browser comparison screen for users who were ever the default browser, are not currently default, and haven’t previously seen the comparison prompt.

Refactors wasEverDefaultBrowser tracking to be set implicitly when AppInstallStore.defaultBrowser is set to true (making wasEverDefaultBrowser read-only), exposes it via UserBrowserProperties, and adjusts existing onboarding/default-browser flows and modal priorities (RemoteMessageModalSurfaceEvaluator to 2, AdditionalDefaultBrowserPromptsImpl to 3) plus tests accordingly.

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[catalinradoiu]

• Add WinBackPromptEvaluator to re-engage users who were previously default browser #8319 👈 (View in Graphite)
• develop

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[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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[cursor]

Missing @SingleInstanceIn annotation unlike other evaluators

Low Severity

WinBackPromptEvaluatorImpl is missing @SingleInstanceIn(scope = AppScope::class) which both RemoteMessageModalSurfaceEvaluatorImpl and AdditionalDefaultBrowserPromptsImpl use. Without it, the @ContributesMultibinding and @ContributesBinding annotations can produce separate unscoped instances. While the class currently has no mutable state, this deviates from the established pattern for ModalEvaluator implementations and could cause subtle issues if state is added later.

 

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