[fenix] Closes https://github.com/mozilla-mobile/fenix/issues/4982: Migrate Gecko files before initializing engine. (https://github.com/mozilla-mobile/fenix/pull/6738)

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

@@ -4,25 +4,32 @@
 
 package org.mozilla.fenix
 
-import mozilla.components.support.ktx.android.content.isMainProcess
+import kotlinx.coroutines.runBlocking
 import mozilla.components.support.migration.FennecMigrator
 
 /**
  * An application class which knows how to migrate Fennec data.
  */
 class MigratingFenixApplication : FenixApplication() {
-    override fun setupApplication() {
-        super.setupApplication()
+    override fun setupInMainProcessOnly() {
+        migrateGeckoBlocking()
 
-        // Same check as is present in super.setupApplication:
-        if (!isMainProcess()) {
-            // If this is not the main process then do not continue with the migration here.
-            // Migration only needs to be done in our app's main process and should not be done in other processes like
-            // a GeckoView child process or the crash handling process. Most importantly we never want to end up in a
-            // situation where we create a GeckoRuntime from the Gecko child process.
-            return
+        super.setupInMainProcessOnly()
+
+        migrateDataAsynchronously()
+    }
+
+    private fun migrateGeckoBlocking() {
+        val migrator = FennecMigrator.Builder(this, this.components.analytics.crashReporter)
+            .migrateGecko()
+            .build()
+
+        runBlocking {
+            migrator.migrateAsync().await()
         }
+    }
 
+    private fun migrateDataAsynchronously() {
         val migrator = FennecMigrator.Builder(this, this.components.analytics.crashReporter)
             .migrateOpenTabs(this.components.core.sessionManager)
             .migrateHistory(this.components.core.historyStorage)

app/src/main/java/org/mozilla/fenix/FenixApplication.kt

@@ -9,6 +9,7 @@ import android.app.Application
 import android.os.Build
 import android.os.Build.VERSION.SDK_INT
 import android.os.StrictMode
+import androidx.annotation.CallSuper
 import androidx.appcompat.app.AppCompatDelegate
 import androidx.core.content.getSystemService
 import io.reactivex.plugins.RxJavaPlugins
@@ -51,17 +52,7 @@ open class FenixApplication : Application() {
     override fun onCreate() {
         super.onCreate()
 
-        setupApplication()
-    }
-
-    open fun setupApplication() {
-        setupCrashReporting()
-        setDayNightTheme()
-
-        setupMegazord()
-        setupLogging()
-        registerRxExceptionHandling()
-        enableStrictMode()
+        setupInAllProcesses()
 
         if (!isMainProcess()) {
             // If this is not the main process then do not continue with the initialization here. Everything that
@@ -71,6 +62,30 @@ open class FenixApplication : Application() {
             return
         }
 
+        setupInMainProcessOnly()
+    }
+
+    @CallSuper
+    open fun setupInAllProcesses() {
+        setupCrashReporting()
+
+        // We want the log messages of all builds to go to Android logcat
+        Log.addSink(AndroidLogSink())
+    }
+
+    @CallSuper
+    open fun setupInMainProcessOnly() {
+        setupMegazord()
+
+        // We want rust logging to go through the log sinks.
+        // This has to happen after initializing the megazord.
+        RustLog.enable()
+
+        setDayNightTheme()
+
+        registerRxExceptionHandling()
+        enableStrictMode()
+
         // Make sure the engine is initialized and ready to use.
         components.core.engine.warmUp()
 
@@ -138,14 +153,6 @@ open class FenixApplication : Application() {
         // no-op, LeakCanary is disabled by default
     }
 
-    private fun setupLogging() {
-        // We want the log messages of all builds to go to Android logcat
-        Log.addSink(AndroidLogSink())
-        // We want rust logging to go through the log sinks.
-        // This has to happen after initializing the megazord.
-        RustLog.enable()
-    }
-
     private fun loadExperiments(): Deferred<Boolean> {
         val experimentsFile = File(filesDir, EXPERIMENTS_JSON_FILENAME)
         val experimentSource = KintoExperimentSource(

app/src/test/java/org/mozilla/fenix/TestApplication.kt

@@ -10,6 +10,7 @@ class TestApplication : FenixApplication() {
 
     override val components = TestComponents(this)
 
-    override fun setupApplication() {
-    }
+    override fun setupInAllProcesses() = Unit
+
+    override fun setupInMainProcessOnly() = Unit
 }