Bug 1837526 - Call StartupTimeline in the Compose Top Sites

Because we are migrating Top Sites to Compose, we want to ensure we
are still recording when top sites are loaded, therefore the call
for StartupTimeline is now called after creating the top sites
compose elements. Calling it here will ensure it will be called
even after we replace the home page recycler with a Compose view.

app/src/main/java/org/mozilla/fenix/home/topsites/TopSites.kt

@@ -104,6 +104,7 @@ fun TopSites(
     onRemoveTopSiteClicked: (topSite: TopSite) -> Unit,
     onSettingsClicked: () -> Unit,
     onSponsorPrivacyClicked: () -> Unit,
+    onTopSitesItemBound: () -> Unit,
 ) {
     val pageCount = ceil((topSites.size.toDouble() / TOP_SITES_PER_PAGE)).toInt()
 
@@ -154,6 +155,7 @@ fun TopSites(
                                     topSiteColors = topSiteColors,
                                     onTopSiteClick = { item -> onTopSiteClick(item) },
                                     onTopSiteLongClick = onTopSiteLongClick,
+                                    onTopSitesItemBound = onTopSitesItemBound,
                                 )
                             }
                         }
@@ -251,6 +253,7 @@ private fun TopSiteItem(
     topSiteColors: TopSiteColors,
     onTopSiteClick: (TopSite) -> Unit,
     onTopSiteLongClick: (TopSite) -> Unit,
+    onTopSitesItemBound: () -> Unit,
 ) {
     var menuExpanded by remember { mutableStateOf(false) }
 
@@ -339,6 +342,10 @@ private fun TopSiteItem(
             }
         }
     }
+
+    LaunchedEffect(Unit) {
+        onTopSitesItemBound()
+    }
 }
 
 /**
@@ -587,6 +594,7 @@ private fun TopSitesPreview() {
                 onRemoveTopSiteClicked = {},
                 onSettingsClicked = {},
                 onSponsorPrivacyClicked = {},
+                onTopSitesItemBound = {},
             )
         }
     }

app/src/main/java/org/mozilla/fenix/home/topsites/TopSitesViewHolder.kt

@@ -9,9 +9,11 @@ import androidx.compose.runtime.Composable
 import androidx.compose.ui.platform.ComposeView
 import androidx.lifecycle.LifecycleOwner
 import mozilla.components.lib.state.ext.observeAsComposableState
+import org.mozilla.fenix.HomeActivity
 import org.mozilla.fenix.components.components
 import org.mozilla.fenix.compose.ComposeViewHolder
 import org.mozilla.fenix.home.sessioncontrol.TopSiteInteractor
+import org.mozilla.fenix.perf.StartupTimeline
 import org.mozilla.fenix.wallpapers.WallpaperState
 
 /**
@@ -49,6 +51,9 @@ class TopSitesViewHolder(
                 onRemoveTopSiteClicked = interactor::onRemoveTopSiteClicked,
                 onSettingsClicked = interactor::onSettingsClicked,
                 onSponsorPrivacyClicked = interactor::onSponsorPrivacyClicked,
+                onTopSitesItemBound = {
+                    StartupTimeline.onTopSitesItemBound(activity = composeView.context as HomeActivity)
+                },
             )
         }
     }

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

@@ -61,6 +61,24 @@ class StartupReportFullyDrawn {
         }
     }
 
+    /**
+     * Instruments "visually complete" cold startup time to homescreen for use with FNPRMS.
+     *
+     * For FNPRMS, we define "visually complete" to be when top sites is loaded with placeholders;
+     * the animation to display top sites will occur after this point, as will the asynchronous
+     * loading of the actual top sites icons. Our focus for visually complete is usability.
+     * There are no tabs available in our FNPRMS tests so they are ignored for this instrumentation.
+     */
+    fun onTopSitesItemBound(state: StartupState, activity: HomeActivity) {
+        if (!isInstrumented &&
+            state is StartupState.Cold && state.destination == HOMESCREEN
+        ) {
+            isInstrumented = true
+
+            attachReportFullyDrawn(activity)
+        }
+    }
+
     private fun attachReportFullyDrawn(activity: Activity, view: View) {
         // For greater accuracy, we could add an onDrawListener instead of a preDrawListener but:
         // - single use onDrawListeners are not built-in and it's non-trivial to write one
@@ -69,4 +87,8 @@ class StartupReportFullyDrawn {
         // should be comparable
         view.doOnPreDraw { activity.reportFullyDrawnSafe(Performance.logger) }
     }
+
+    private fun attachReportFullyDrawn(activity: Activity) {
+        activity.reportFullyDrawnSafe(Performance.logger)
+    }
 }

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

@@ -54,6 +54,13 @@ object StartupTimeline {
         reportFullyDrawn.onTopSitesItemBound(state, holder)
     }
 
+    /**
+     * Instruments "visually complete" cold startup time to homescreen for use with FNPRMS.
+     */
+    fun onTopSitesItemBound(activity: HomeActivity) {
+        reportFullyDrawn.onTopSitesItemBound(state, activity)
+    }
+
     private fun advanceState(startingActivity: StartupActivity) {
         state = StartupTimelineStateMachine.getNextState(state, startingActivity)
     }