Launch Link Eagerly with new ConfirmationDefinition

[toluo-stripe]

Summary (Proof of Concept)

This is PR adds link_express as a new confirmation option. This is the scenario where Link is launched eagerly as 2FA dialog (see screenshot below).

link_express will be launched with a LinkAccount, and after the 2FA is done, this confirmation definition returns a NextStep to launch native_link with an updated LinkAccount.

Why are we passing LinkAccount around? LinkAccountManager is scoped to the module that uses it, so the Link auth state in paymentsheet does not exist in NativeLink. We initialize LinkAccountManager with a LinkAccount if provided.

Why a new ConfirmationDefinition?
I chose to do it this way because I want to keep LinkActivity (native link) simple. This eager flow would add more complexity and require at least a small refactor because of the translucent background and other small things like navigation. I'm open to other ideas.

Motivation

Testing

• Added tests
• Modified tests
• Manually verified

Screenshots

Screen.Recording.2025-01-21.at.9.30.41.AM.mov

Changelog

[github-actions]

Diffuse output:

OLD: identity-example-release-base.apk (signature: V1, V2)
NEW: identity-example-release-pr.apk (signature: V1, V2)

          │          compressed          │         uncompressed         
          ├───────────┬───────────┬──────┼───────────┬───────────┬──────
 APK      │ old       │ new       │ diff │ old       │ new       │ diff 
──────────┼───────────┼───────────┼──────┼───────────┼───────────┼──────
      dex │     2 MiB │     2 MiB │  0 B │   4.1 MiB │   4.1 MiB │  0 B 
     arsc │     1 MiB │     1 MiB │  0 B │     1 MiB │     1 MiB │  0 B 
 manifest │   2.3 KiB │   2.3 KiB │  0 B │     8 KiB │     8 KiB │  0 B 
      res │ 302.6 KiB │ 302.6 KiB │  0 B │ 456.7 KiB │ 456.7 KiB │  0 B 
   native │   6.2 MiB │   6.2 MiB │  0 B │  15.8 MiB │  15.8 MiB │  0 B 
    asset │   7.1 KiB │   7.1 KiB │  0 B │   6.9 KiB │   6.9 KiB │  0 B 
    other │  90.4 KiB │  90.4 KiB │ +9 B │ 170.7 KiB │ 170.7 KiB │  0 B 
──────────┼───────────┼───────────┼──────┼───────────┼───────────┼──────
    total │   9.6 MiB │   9.6 MiB │ +9 B │  21.5 MiB │  21.5 MiB │  0 B 

 DEX     │ old   │ new   │ diff      
─────────┼───────┼───────┼───────────
   files │     1 │     1 │ 0         
 strings │ 19975 │ 19975 │ 0 (+0 -0) 
   types │  6193 │  6193 │ 0 (+0 -0) 
 classes │  4985 │  4985 │ 0 (+0 -0) 
 methods │ 29820 │ 29820 │ 0 (+0 -0) 
  fields │ 17538 │ 17538 │ 0 (+0 -0) 

 ARSC    │ old  │ new  │ diff 
─────────┼──────┼──────┼──────
 configs │  164 │  164 │  0   
 entries │ 3624 │ 3624 │  0

APK

   compressed    │   uncompressed   │                                           
──────────┬──────┼───────────┬──────┤                                           
 size     │ diff │ size      │ diff │ path                                      
──────────┼──────┼───────────┼──────┼───────────────────────────────────────────
 28.5 KiB │ +6 B │  63.1 KiB │  0 B │ ∆ META-INF/CERT.SF                        
 25.4 KiB │ +4 B │    63 KiB │  0 B │ ∆ META-INF/MANIFEST.MF                    
    271 B │ -1 B │     120 B │  0 B │ ∆ META-INF/version-control-info.textproto 
──────────┼──────┼───────────┼──────┼───────────────────────────────────────────
 54.2 KiB │ +9 B │ 126.2 KiB │  0 B │ (total)

[samer-stripe]

I think this makes sense as a confirmation definition since we are expecting this to be a payment flow that immediately completes PaymentSheet.

A side note, I think this is the first case of a three-step confirmation flow we have in the repo.

[toluo-stripe]

This is a design question mark. I feel like it's safe but would love to discuss.

[amk-stripe]

I'm kinda surprised that all these fields are ignored on parcel -- how do we actually use the LinkAccount if none of the fields are parcelized? Or am I misunderstanding?