Completed AuthTab Implementation

[noguier]

Thank you for your contribution to Braintree.

Summary of changes

• added AuthTabInternalClient, that support both AuthTab and ChromeCustomTab.
  Note: ACTIVITY_NEW_TASK is not supported for AuthTab
• removed ChromeCustomTabsInternalClient,
• modified ComposeActivity & DemoActivitySingleTop to accept the above changes. Added checks to use Authtab or ChromeCustomTab depending on the device
• added toast visuals to see whether or not the AuthTab is supported
• cleared intent data after handling incomplete browser switch to prevent displaying stale success data from a previous request

Checklist

• Added a changelog entry

Authors

List GitHub usernames for everyone who contributed to this pull request.

• @noguier

[tdchow]

I was thinking of potential ways to streamline the integration steps for Browser Switch with Auth Tab.

What if we removed the exposed AuthTabCallback used for the Auth Tab flow, but internally set the AuthTabIntent.registerActivityResultLauncher. When the launcher callback is invoked with a result, we could store it in the BrowserSwitchClient class and use that result when the caller of the SDK invokes BrowserSwitchClient.completeRequest(), instead of the passed in intent.

This way the caller of the Browser Switch SDK does not need to add additional logic for AuthTab and can use the existing API interface.

@noguier @saperi22 - I haven't completely vetted this approach but wanted to get your thoughts!

edit: This makes the assumption that the AuthTabIntent.registerActivityResultLauncher is invoked before onResume or onNewIntent in the calling Activity. I ran a few tests and this seems to be the behavior.

[tdchow]

Chatted with @noguier on a call regarding my above comment and determined that the changes should be outside of the scope of this PR. We'll create a follow up ticket to investigate.

[saperi22]

This makes the assumption that the AuthTabIntent.registerActivityResultLauncher is invoked before onResume or onNewIntent in the calling Activity. I ran a few tests and this seems to be the behavior.

I'm not sure if this is always true. Any official documentation on this would be great, but there's also not enough information to be pushing back on this right now.

[saperi22]

@noguier we could probably add detekt in one of our future PRs to catch some styling issues.

[noguier]

@saperi22 regarding @tdchow quote here:

This makes the assumption that the AuthTabIntent.registerActivityResultLauncher is invoked before onResume or onNewIntent in the calling Activity. I ran a few tests and this seems to be the behavior.

Based on this section, specifically :

Before launching an Auth Tab, declare an ActivityResultLauncher that takes an ActivityResultCaller as well as an ActivityResultCallback. This is done before the activity or fragment is created.

So, to my understanding as long as we call registerActivityResultLauncher in onCreate, Tim's assumption will always hold. Please, correct me if I am wrong.

[tdchow]

Changes look good! just had a few non blocking comments.