[fenix] For https://github.com/mozilla-mobile/fenix/issues/21921: add and register MarkersFragmentLifecycleCallbacks.

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

@@ -99,6 +99,7 @@ import org.mozilla.fenix.library.historymetadata.HistoryMetadataGroupFragmentDir
 import org.mozilla.fenix.library.recentlyclosed.RecentlyClosedFragmentDirections
 import org.mozilla.fenix.onboarding.DefaultBrowserNotificationWorker
 import org.mozilla.fenix.perf.MarkersActivityLifecycleCallbacks
+import org.mozilla.fenix.perf.MarkersFragmentLifecycleCallbacks
 import org.mozilla.fenix.perf.Performance
 import org.mozilla.fenix.perf.PerformanceInflater
 import org.mozilla.fenix.perf.ProfilerMarkers
@@ -187,6 +188,8 @@ open class HomeActivity : LocaleAwareAppCompatActivity(), NavHostActivity {
         val startTimeProfiler = components.core.engine.profiler?.getProfilerTime()
 
         components.strictMode.attachListenerToDisablePenaltyDeath(supportFragmentManager)
+        MarkersFragmentLifecycleCallbacks.register(supportFragmentManager, components.core.engine)
+
         // There is disk read violations on some devices such as samsung and pixel for android 9/10
         components.strictMode.resetAfter(StrictMode.allowThreadDiskReads()) {
             // Theme setup should always be called before super.onCreate

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

@@ -0,0 +1,119 @@
+/* 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.content.Context
+import android.os.Bundle
+import android.view.View
+import androidx.fragment.app.Fragment
+import androidx.fragment.app.FragmentManager
+import mozilla.components.concept.engine.Engine
+
+/**
+ * Adds a profiler marker for each fragment lifecycle callbacks. The callbacks are called by the
+ * super method (e.g. [Fragment.onCreate] so the markers occur sometime during the execution of
+ * our implementation (e.g. [org.mozilla.fenix.home.HomeFragment.onCreate]) rather than at the
+ * beginning or end of that method.
+ */
+@Suppress("TooManyFunctions") // it's the interface so we don't have a choice
+class MarkersFragmentLifecycleCallbacks(
+    private val engine: Engine
+) : FragmentManager.FragmentLifecycleCallbacks() {
+
+    private fun shouldSkip(): Boolean {
+        return engine.profiler?.isProfilerActive() != true
+    }
+
+    override fun onFragmentAttached(fm: FragmentManager, f: Fragment, context: Context) {
+        if (shouldSkip()) {
+            return
+        }
+
+        engine.profiler?.addMarker(MARKER_NAME, "${f::class.simpleName}.onAttach (via callbacks)")
+    }
+
+    override fun onFragmentPaused(fm: FragmentManager, f: Fragment) {
+        if (shouldSkip()) {
+            return
+        }
+
+        engine.profiler?.addMarker(MARKER_NAME, "${f::class.simpleName}.onPause (via callbacks)")
+    }
+
+    override fun onFragmentStopped(fm: FragmentManager, f: Fragment) {
+        if (shouldSkip()) {
+            return
+        }
+
+        engine.profiler?.addMarker(MARKER_NAME, "${f::class.simpleName}.onStop (via callbacks)")
+    }
+
+    override fun onFragmentDestroyed(fm: FragmentManager, f: Fragment) {
+        if (shouldSkip()) {
+            return
+        }
+
+        engine.profiler?.addMarker(MARKER_NAME, "${f::class.simpleName}.onDestroy (via callbacks)")
+    }
+
+    override fun onFragmentDetached(fm: FragmentManager, f: Fragment) {
+        if (shouldSkip()) {
+            return
+        }
+
+        engine.profiler?.addMarker(MARKER_NAME, "${f::class.simpleName}.onDetach (via callbacks)")
+    }
+
+    override fun onFragmentCreated(fm: FragmentManager, f: Fragment, savedInstanceState: Bundle?) {
+        if (shouldSkip()) {
+            return
+        }
+
+        engine.profiler?.addMarker(MARKER_NAME, "${f::class.simpleName}.onCreate (via callbacks)")
+    }
+
+    override fun onFragmentViewCreated(fm: FragmentManager, f: Fragment, v: View, savedInstanceState: Bundle?) {
+        if (shouldSkip()) {
+            return
+        }
+
+        engine.profiler?.addMarker(MARKER_NAME, "${f::class.simpleName}.onViewCreated (via callbacks)")
+    }
+
+    override fun onFragmentStarted(fm: FragmentManager, f: Fragment) {
+        if (shouldSkip()) {
+            return
+        }
+
+        engine.profiler?.addMarker(MARKER_NAME, "${f::class.simpleName}.onStart (via callbacks)")
+    }
+
+    override fun onFragmentResumed(fm: FragmentManager, f: Fragment) {
+        if (shouldSkip()) {
+            return
+        }
+
+        engine.profiler?.addMarker(MARKER_NAME, "${f::class.simpleName}.onResume (via callbacks)")
+    }
+
+    override fun onFragmentViewDestroyed(fm: FragmentManager, f: Fragment) {
+        if (shouldSkip()) {
+            return
+        }
+
+        engine.profiler?.addMarker(MARKER_NAME, "${f::class.simpleName}.onViewDestroyed (via callbacks)")
+    }
+
+    companion object {
+        const val MARKER_NAME = "Fragment Lifecycle"
+
+        fun register(supportFragmentManager: FragmentManager, engine: Engine) {
+            val callbacks = MarkersFragmentLifecycleCallbacks(engine)
+
+            // We do recursive because the NavHostFragment adds additional fragments as subfragments.
+            supportFragmentManager.registerFragmentLifecycleCallbacks(callbacks, true)
+        }
+    }
+}