For #8172: Add a new 'E_Fennec_To_Fenix_Migrated' Leanplum event

This new event will be sent when the user has successfully migrated from Fennec
to Fenix.
This event will only be sent to Leanplum and not to the other telemetry
services like Glean or Adjust.

Co-authored-by: ValentinTimisica <valentin.timisica@softvision.ro>

app/src/main/java/org/mozilla/fenix/components/metrics/GleanMetricsService.kt

@@ -494,6 +494,7 @@ private val Event.wrapper: EventWrapper<*>?
         is Event.InteractWithSearchURLArea -> null
         is Event.ClearedPrivateData -> null
         is Event.DismissedOnboarding -> null
+        is Event.FennecToFenixMigrated -> null
     }
 
 class GleanMetricsService(private val context: Context) : MetricsService {

app/src/main/java/org/mozilla/fenix/components/metrics/LeanplumMetricsService.kt

@@ -30,6 +30,7 @@ private val Event.name: String?
         is Event.SyncAuthSignOut -> "E_Sign_Out_FxA"
         is Event.ClearedPrivateData -> "E_Cleared_Private_Data"
         is Event.DismissedOnboarding -> "E_Dismissed_Onboarding"
+        is Event.FennecToFenixMigrated -> "E_Fennec_To_Fenix_Migrated"
 
         // Do not track other events in Leanplum
         else -> ""

app/src/main/java/org/mozilla/fenix/components/metrics/Metrics.kt

@@ -149,6 +149,7 @@ sealed class Event {
     object RightsTapped : Event()
     object LicensingTapped : Event()
     object LibrariesThatWeUseTapped : Event()
+    object FennecToFenixMigrated : Event()
 
     // Interaction events with extras
 

app/src/main/java/org/mozilla/fenix/migration/MigrationTelemetryListener.kt

@@ -0,0 +1,32 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+* License, v. 2.0. If a copy of the MPL was not distributed with this
+file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.fenix
+
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.flow.collect
+import mozilla.components.lib.state.ext.flowScoped
+import mozilla.components.support.base.log.logger.Logger
+import mozilla.components.support.migration.state.MigrationProgress
+import mozilla.components.support.migration.state.MigrationStore
+import org.mozilla.fenix.components.metrics.Event
+import org.mozilla.fenix.components.metrics.MetricController
+
+class MigrationTelemetryListener(
+    private val metrics: MetricController,
+    private val store: MigrationStore
+) {
+    @UseExperimental(ExperimentalCoroutinesApi::class)
+    fun start() {
+        // Observe for migration completed.
+        store.flowScoped { flow ->
+            flow.collect { state ->
+                Logger("MigrationTelemetryListener").debug("Migration state: ${state.progress}")
+                if (state.progress == MigrationProgress.COMPLETED) {
+                    metrics.track(Event.FennecToFenixMigrated)
+                }
+            }
+        }
+    }
+}

app/src/migration/java/org/mozilla/fenix/MigratingFenixApplication.kt

@@ -42,6 +42,13 @@ class MigratingFenixApplication : FenixApplication() {
         )
     }
 
+    val migrationTelemetryListener by lazy {
+        MigrationTelemetryListener(
+            components.analytics.metrics,
+            components.migrationStore
+        )
+    }
+
     override fun setupInMainProcessOnly() {
         // These migrations need to run before regular initialization happens.
         migrateBlocking()
@@ -55,6 +62,7 @@ class MigratingFenixApplication : FenixApplication() {
 
         // The rest of the migrations can happen now.
         migrationPushSubscriber.start()
+        migrationTelemetryListener.start()
         migrator.startMigrationIfNeeded(components.migrationStore, MigrationService::class.java)
     }
 

docs/mma.md

@@ -226,6 +226,11 @@ Here is the list of current Events sent, which can be found here in the code bas
     <td>The user finished onboarding. Could be triggered by pressing "start browsing," opening settings, or invoking a search.</td>
     <td><a href="https://github.com/mozilla-mobile/fenix/pull/3459#issuecomment-502191109">#3459</a></td>
   </tr>
+  <tr>
+    <td>`E_Fennec_To_Fenix_Migrated`</td>
+    <td>The user has just migrated from Fennec to Fenix.</td>
+    <td><a href="https://github.com/mozilla-mobile/fenix/pull/8208#issuecomment-584040440">#8208</a></td>
+  </tr>
 </table>
 
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