Proxy Custom Tabs through a stub Activity under our control.

app/src/main/AndroidManifest.xml

@@ -407,6 +407,9 @@
             android:name=".donate.donationreminder.DonationReminderActivity"
             android:windowSoftInputMode="adjustResize"/>
 
+        <activity
+            android:name=".activity.CustomTabProxyActivity" />
+
         <provider
             android:name=".WikipediaFileProvider"
             android:authorities="${applicationId}.fileprovider"

app/src/main/java/org/wikipedia/activity/CustomTabProxyActivity.kt

@@ -0,0 +1,70 @@
+package org.wikipedia.activity
+
+import android.content.Context
+import android.content.Intent
+import android.os.Bundle
+import androidx.appcompat.app.AppCompatActivity
+import org.wikipedia.extensions.parcelable
+import org.wikipedia.extensions.parcelableExtra
+import org.wikipedia.util.CustomTabsUtil
+
+class CustomTabProxyActivity : AppCompatActivity() {
+    private var tabUrl: String? = null
+    private var nextIntent: Intent? = null
+
+    private var isTabLaunched = false
+
+    public override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+
+        if (savedInstanceState == null) {
+            tabUrl = intent.getStringExtra(EXTRA_TAB_URL)
+            nextIntent = intent.parcelableExtra(EXTRA_NEXT_INTENT)
+        } else {
+            tabUrl = savedInstanceState.getString(EXTRA_TAB_URL)
+            nextIntent = savedInstanceState.parcelable(EXTRA_NEXT_INTENT)
+            isTabLaunched = savedInstanceState.getBoolean(EXTRA_TAB_LAUNCHED, false)
+        }
+    }
+
+    override fun onSaveInstanceState(outState: Bundle) {
+        super.onSaveInstanceState(outState)
+        outState.putString(EXTRA_TAB_URL, tabUrl)
+        outState.putBoolean(EXTRA_TAB_LAUNCHED, isTabLaunched)
+    }
+
+    override fun onResume() {
+        super.onResume()
+
+        if (!isTabLaunched && !tabUrl.isNullOrEmpty()) {
+            CustomTabsUtil.openInCustomTab(this, tabUrl!!)
+            isTabLaunched = true
+            return
+        }
+
+        finish()
+
+        if (nextIntent != null) {
+            startActivity(nextIntent)
+            nextIntent = null
+        }
+    }
+
+    companion object {
+        private const val EXTRA_TAB_URL = "extra_tab_url"
+        private const val EXTRA_NEXT_INTENT = "extra_next_intent"
+        private const val EXTRA_TAB_LAUNCHED = "extra_tab_launched"
+
+        fun newIntent(context: Context, customTabUrl: String): Intent {
+            return Intent(context, CustomTabProxyActivity::class.java)
+                .putExtra(EXTRA_TAB_URL, customTabUrl)
+        }
+
+        fun newCancelingIntent(context: Context, nextIntent: Intent?): Intent {
+            return Intent(context, CustomTabProxyActivity::class.java)
+                .putExtra(EXTRA_NEXT_INTENT, nextIntent).also {
+                    it.flags = Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TOP
+                }
+        }
+    }
+}

app/src/main/java/org/wikipedia/donate/DonateDialog.kt

@@ -16,13 +16,13 @@ import org.wikipedia.BuildConfig
 import org.wikipedia.R
 import org.wikipedia.WikipediaApp
 import org.wikipedia.activity.BaseActivity
+import org.wikipedia.activity.CustomTabProxyActivity
 import org.wikipedia.analytics.eventplatform.DonorExperienceEvent
 import org.wikipedia.databinding.DialogDonateBinding
 import org.wikipedia.dataclient.donate.CampaignCollection
 import org.wikipedia.donate.donationreminder.DonationReminderHelper
 import org.wikipedia.page.ExtendedBottomSheetDialogFragment
 import org.wikipedia.settings.Prefs
-import org.wikipedia.util.CustomTabsUtil
 import org.wikipedia.util.FeedbackUtil
 import org.wikipedia.util.Resource
 
@@ -172,7 +172,7 @@ class DonateDialog : ExtendedBottomSheetDialogFragment() {
             }.orEmpty()
             val donateUrl = url ?: context.getString(R.string.donate_url, formattedCampaignId,
                 WikipediaApp.instance.languageState.systemLanguageCode, BuildConfig.VERSION_NAME)
-            CustomTabsUtil.openInCustomTab(context, donateUrl)
+            context.startActivity(CustomTabProxyActivity.newIntent(context, donateUrl))
         }
     }
 }

app/src/main/java/org/wikipedia/page/PageActivity.kt

@@ -37,6 +37,7 @@ import org.wikipedia.Constants.InvokeSource
 import org.wikipedia.R
 import org.wikipedia.WikipediaApp
 import org.wikipedia.activity.BaseActivity
+import org.wikipedia.activity.CustomTabProxyActivity
 import org.wikipedia.activity.SingleWebViewActivity
 import org.wikipedia.analytics.eventplatform.BreadCrumbLogEvent
 import org.wikipedia.analytics.eventplatform.DonorExperienceEvent
@@ -560,8 +561,9 @@ class PageActivity : BaseActivity(), PageFragment.Callback, LinkPreviewDialog.Lo
                             } ?: run {
                                 DonorExperienceEvent.logAction("impression", "webpay_processed", wiki.languageCode)
                             }
-                            startActivity(SingleWebViewActivity.newIntent(this@PageActivity, uri.toString(),
-                                true, pageFragment.title, pageContentInfo))
+                            val thanksIntent = SingleWebViewActivity.newIntent(this@PageActivity, uri.toString(),
+                                true, pageFragment.title, pageContentInfo)
+                            startActivity(CustomTabProxyActivity.newCancelingIntent(this, thanksIntent))
                             finish()
                             return
                         }