Fix browser redirect on firefox browser.

[michelleb-stripe]

Summary

Make the StripeBrowserLauncherActivity a single instance so that it clears the activities up until the StripeBrowserLauncher. After this change the redirect will now work on the firefox mobile browser.

I found this similar issue: https://stackoverflow.com/questions/55077642/android-deep-link-firefox-like-chrome

For us the concern about the extras is less relevant because in our code base onResult is called which just calls finish (it also then calls onNewIntent). It does not use the extras.

Attempt to fix #3952

Testing

• Added tests
• Modified tests
• Manually verified

[github-actions]

Diffuse output:

OLD: paymentsheet-example-release-master.apk (signature: none)
NEW: paymentsheet-example-release-pr.apk (signature: none)

          │          compressed          │         uncompressed         
          ├───────────┬───────────┬──────┼───────────┬───────────┬──────
 APK      │ old       │ new       │ diff │ old       │ new       │ diff 
──────────┼───────────┼───────────┼──────┼───────────┼───────────┼──────
      dex │  11.4 MiB │  11.4 MiB │  0 B │    39 MiB │    39 MiB │  0 B 
     arsc │   1.3 MiB │   1.3 MiB │  0 B │   1.3 MiB │   1.3 MiB │  0 B 
 manifest │   2.5 KiB │   2.5 KiB │ +1 B │  10.5 KiB │  10.5 KiB │  0 B 
      res │ 695.6 KiB │ 695.6 KiB │ -2 B │     1 MiB │     1 MiB │  0 B 
    asset │  23.9 KiB │  23.9 KiB │  0 B │  36.9 KiB │  36.9 KiB │  0 B 
    other │ 150.7 KiB │ 150.7 KiB │  0 B │ 308.1 KiB │ 308.1 KiB │  0 B 
──────────┼───────────┼───────────┼──────┼───────────┼───────────┼──────
    total │  13.6 MiB │  13.6 MiB │ -1 B │  41.7 MiB │  41.7 MiB │  0 B 


         │          raw           │           unique            
         ├────────┬────────┬──────┼────────┬────────┬───────────
 DEX     │ old    │ new    │ diff │ old    │ new    │ diff      
─────────┼────────┼────────┼──────┼────────┼────────┼───────────
   files │      3 │      3 │    0 │        │        │           
 strings │ 177066 │ 177066 │    0 │ 164684 │ 164684 │ 0 (+0 -0) 
   types │  31122 │  31122 │    0 │  29644 │  29644 │ 0 (+0 -0) 
 classes │  27364 │  27364 │    0 │  27364 │  27364 │ 0 (+0 -0) 
 methods │ 157470 │ 157470 │    0 │ 153493 │ 153493 │ 0 (+0 -0) 
  fields │ 107721 │ 107721 │    0 │ 107431 │ 107431 │ 0 (+0 -0) 


 ARSC    │ old  │ new  │ diff 
─────────┼──────┼──────┼──────
 configs │  292 │  292 │  0   
 entries │ 4310 │ 4310 │  0

APK

   compressed   │  uncompressed   │                       
─────────┬──────┼──────────┬──────┤                       
 size    │ diff │ size     │ diff │ path                  
─────────┼──────┼──────────┼──────┼───────────────────────
   984 B │ -2 B │    882 B │  0 B │ ∆ res/-I.9.png        
 2.5 KiB │ +1 B │ 10.5 KiB │  0 B │ ∆ AndroidManifest.xml 
─────────┼──────┼──────────┼──────┼───────────────────────
 3.5 KiB │ -1 B │ 11.4 KiB │  0 B │ (total)

MANIFEST

@@ -97,3 +97,3 @@
         android:exported=true
-        android:launchMode=1
+        android:launchMode=2
         android:name=com.stripe.android.payments.StripeBrowserLauncherActivity

[mshafrir-stripe]

Were you able to verify the behavior with Custom Tabs and without custom tabs across different browsers?

From https://inthecheesefactory.com/blog/understand-android-activity-launchmode/en, "This mode is rarely used.". I wonder if there are any negative tradeoffs from using this mode?

[michelleb-stripe]

I am testing this with Opera, Firefox, and Chrome browsers. With singleTop it only works with Chrome and Opera. With singleTask and singleInstance it works with Firefox, Chrome, and Opera.

[michelleb-stripe]

Are there additional browsers you think would be worth testing with?

[michelleb-stripe]

Just wanted to check on your intent of launchMode: singleTop (the original). Was your hope to destroy the activities above StripeBrowserLauncherActivity? In this case either singleTask or singleInstance would both work.

[mshafrir-stripe]

I am testing this with Opera, Firefox, and Chrome browsers. With singleTop it only works with Chrome and Opera. With singleTask and singleInstance it works with Firefox, Chrome, and Opera.

Is this also true for Custom Tabs vs not?

I think this change is fine, I was mainly wondering if there are any tradeoffs. Also sounds like singleTask is a smaller scope version of singleInstance. Should we use that instead?

[michelleb-stripe]

yep! singleTask works for chrome tabs as well.

[michelleb-stripe]

Updated to singleTask

[mshafrir-stripe]

Doesn't have to be in this PR, but would be nice to add a comment as to why this is necessary.