for #13479, added a VisualCompletenessQueue.kt class to handle all the functionality related to visual completeness

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

@@ -159,15 +159,15 @@ open class FenixApplication : LocaleAwareApplication(), Provider {
     }
 
     private fun initVisualCompletenessQueueAndQueueTasks() {
-        val taskQueue = components.performance.visualCompletenessQueue
+        val queue = components.performance.visualCompletenessQueue.queue
 
         fun initQueue() {
-            registerActivityLifecycleCallbacks(PerformanceActivityLifecycleCallbacks(taskQueue))
+            registerActivityLifecycleCallbacks(PerformanceActivityLifecycleCallbacks(queue))
         }
 
         fun queueInitExperiments() {
             if (settings().isExperimentationEnabled) {
-                taskQueue.runIfReadyOrQueue {
+                queue.runIfReadyOrQueue {
                     Experiments.initialize(
                         applicationContext = applicationContext,
                         onExperimentsUpdated = {
@@ -188,7 +188,7 @@ open class FenixApplication : LocaleAwareApplication(), Provider {
         }
 
         fun queueInitStorageAndServices() {
-            components.performance.visualCompletenessQueue.runIfReadyOrQueue {
+            components.performance.visualCompletenessQueue.queue.runIfReadyOrQueue {
                 GlobalScope.launch(Dispatchers.IO) {
                     logger.info("Running post-visual completeness tasks...")
                     logElapsedTime(logger, "Storage initialization") {
@@ -208,7 +208,7 @@ open class FenixApplication : LocaleAwareApplication(), Provider {
 
         fun queueMetrics() {
             if (SDK_INT >= Build.VERSION_CODES.O) { // required by StorageStatsMetrics.
-                taskQueue.runIfReadyOrQueue {
+                queue.runIfReadyOrQueue {
                     // Because it may be slow to capture the storage stats, it might be preferred to
                     // create a WorkManager task for this metric, however, I ran out of
                     // implementation time and WorkManager is harder to test.

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

@@ -21,7 +21,6 @@ import androidx.annotation.VisibleForTesting
 import androidx.annotation.VisibleForTesting.PROTECTED
 import androidx.appcompat.app.ActionBar
 import androidx.appcompat.widget.Toolbar
-import androidx.core.view.doOnPreDraw
 import androidx.lifecycle.lifecycleScope
 import androidx.navigation.NavDestination
 import androidx.navigation.NavDirections
@@ -56,7 +55,6 @@ import mozilla.components.support.ktx.android.content.share
 import mozilla.components.support.ktx.kotlin.isUrl
 import mozilla.components.support.ktx.kotlin.toNormalizedUrl
 import mozilla.components.support.locale.LocaleAwareAppCompatActivity
-import mozilla.components.support.utils.RunWhenReadyQueue
 import mozilla.components.support.utils.SafeIntent
 import mozilla.components.support.utils.toSafeIntent
 import mozilla.components.support.webextensions.WebExtensionPopupFeature
@@ -104,6 +102,7 @@ import org.mozilla.fenix.tabtray.TabTrayDialogFragmentDirections
 import org.mozilla.fenix.theme.DefaultThemeManager
 import org.mozilla.fenix.theme.ThemeManager
 import org.mozilla.fenix.utils.BrowsersCache
+import java.lang.ref.WeakReference
 
 /**
  * The main activity of the application. The application is primarily a single Activity (this one)
@@ -122,7 +121,6 @@ open class HomeActivity : LocaleAwareAppCompatActivity(), NavHostActivity {
 
     private var isVisuallyComplete = false
 
-    private var visualCompletenessQueue: RunWhenReadyQueue? = null
     private var privateNotificationObserver: PrivateNotificationFeature<PrivateNotificationService>? = null
 
     private var isToolbarInflated = false
@@ -164,13 +162,8 @@ open class HomeActivity : LocaleAwareAppCompatActivity(), NavHostActivity {
 
         // Must be after we set the content view
         if (isVisuallyComplete) {
-            rootContainer.doOnPreDraw {
-                // This delay is temporary. We are delaying 5 seconds until the performance
-                // team can locate the real point of visual completeness.
-                it.postDelayed({
-                    visualCompletenessQueue!!.ready()
-                }, delay)
-            }
+            components.performance.visualCompletenessQueue
+                .attachViewToRunVisualCompletenessQueueLater(WeakReference(rootContainer))
         }
 
         sessionObserver = UriOpenedObserver(this)
@@ -678,9 +671,8 @@ open class HomeActivity : LocaleAwareAppCompatActivity(), NavHostActivity {
      * The root container is null at this point, so let the HomeActivity know that
      * we are visually complete.
      */
-    fun postVisualCompletenessQueue(visualCompletenessQueue: RunWhenReadyQueue) {
+    fun setVisualCompletenessQueueReady() {
         isVisuallyComplete = true
-        this.visualCompletenessQueue = visualCompletenessQueue
     }
 
     private fun captureSnapshotTelemetryMetrics() = CoroutineScope(Dispatchers.IO).launch {
@@ -717,7 +709,6 @@ open class HomeActivity : LocaleAwareAppCompatActivity(), NavHostActivity {
         const val PRIVATE_BROWSING_MODE = "private_browsing_mode"
         const val EXTRA_DELETE_PRIVATE_TABS = "notification_delete_and_open"
         const val EXTRA_OPENED_FROM_NOTIFICATION = "notification_open"
-        const val delay = 5000L
         const val START_IN_RECENTS_SCREEN = "start_in_recents_screen"
 
         // PWA must have been used within last 30 days to be considered "recently used" for the

app/src/main/java/org/mozilla/fenix/components/PerformanceComponent.kt

@@ -5,10 +5,11 @@
 package org.mozilla.fenix.components
 
 import mozilla.components.support.utils.RunWhenReadyQueue
+import org.mozilla.fenix.perf.VisualCompletenessQueue
 
 /**
  * Component group for all functionality related to performance.
  */
 class PerformanceComponent {
-    val visualCompletenessQueue by lazy { RunWhenReadyQueue() }
+    val visualCompletenessQueue by lazy { VisualCompletenessQueue(RunWhenReadyQueue()) }
 }

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

@@ -725,7 +725,7 @@ class GleanMetricsService(private val context: Context) : MetricsService {
 
         // The code below doesn't need to execute immediately, so we'll add them to the visual
         // completeness task queue to be run later.
-        context.components.performance.visualCompletenessQueue.runIfReadyOrQueue {
+        context.components.performance.visualCompletenessQueue.queue.runIfReadyOrQueue {
             // We have to initialize Glean *on* the main thread, because it registers lifecycle
             // observers. However, the activation ping must be sent *off* of the main thread,
             // because it calls Google ad APIs that must be called *off* of the main thread.

app/src/main/java/org/mozilla/fenix/perf/VisualCompletenessQueue.kt

@@ -0,0 +1,33 @@
+/* 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.perf
+
+import android.view.View
+import androidx.core.view.doOnPreDraw
+import mozilla.components.support.utils.RunWhenReadyQueue
+import java.lang.ref.WeakReference
+
+/**
+ * class for all functionality related to Visual completeness queue
+ */
+class VisualCompletenessQueue(val queue: RunWhenReadyQueue) {
+    @Suppress("MagicNumber")
+    val delay = 5000L
+
+    /**
+     *
+     * @param containerWeakReference a weak reference to the root view of a view hierarchy. Weak
+     * reference is to avoid memory leak.
+     */
+    fun attachViewToRunVisualCompletenessQueueLater(containerWeakReference: WeakReference<View>) {
+        containerWeakReference.get()?.doOnPreDraw {
+            // This delay is temporary. We are delaying 5 seconds until the performance
+            // team can locate the real point of visual completeness.
+            it.postDelayed({
+                queue.ready()
+            }, delay)
+        }
+    }
+}

app/src/main/java/org/mozilla/fenix/session/PerformanceActivityLifecycleCallbacks.kt

@@ -51,7 +51,7 @@ class PerformanceActivityLifecycleCallbacks(
         if (activity is HomeActivity) {
             // We should delay the visualCompletenessQueue when reaching the HomeActivity
             // to ensure all tasks are delayed until after visual completeness
-            activity.postVisualCompletenessQueue(visualCompletenessQueue)
+            activity.setVisualCompletenessQueueReady()
         } else if (shouldStartVisualCompletenessQueueImmediately()) {
             // If we do not go through the home activity, we have to start the tasks
             // immediately to avoid spending time implementing it.