For #19881 add telemetry for start on Home.

app/metrics.yaml

@@ -5813,3 +5813,30 @@ set_default_setting_experiment:
     notification_emails:
       - firefox-android-team@mozilla.com
     expires: "2021-10-01"
+start_on_home:
+  enter_home_screen:
+    type: event
+    description: |
+      Know how often user lands on Homescreen upon opening the app.
+    bugs:
+      - https://github.com/mozilla-mobile/fenix/issues/19881
+    data_reviews:
+      - https://github.com/mozilla-mobile/fenix/pull/19885
+    data_sensitivity:
+      - interaction
+    notification_emails:
+      - fenix-core@mozilla.com
+    expires: "2022-06-16"
+  open_tabs_tray:
+    type: event
+    description: |
+      Know how often users open the tab tray.
+    bugs:
+      - https://github.com/mozilla-mobile/fenix/issues/19881
+    data_reviews:
+      - https://github.com/mozilla-mobile/fenix/pull/19885
+    data_sensitivity:
+      - interaction
+    notification_emails:
+      - fenix-core@mozilla.com
+    expires: "2022-06-16"

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

@@ -223,6 +223,8 @@ open class HomeActivity : LocaleAwareAppCompatActivity(), NavHostActivity {
             shouldNavigateBrowserFragmentOnCouldStart(savedInstanceState)
         ) {
             navigateToBrowserOnColdStart()
+        } else {
+            components.analytics.metrics.track(Event.StartOnHomeEnterHomeScreen)
         }
 
         Performance.processIntentIfPerformanceTest(intent, this)

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

@@ -239,6 +239,10 @@ sealed class Event {
     // Browser Toolbar
     object BrowserToolbarHomeButtonClicked : Event()
 
+    // Start on Home
+    object StartOnHomeEnterHomeScreen : Event()
+    object StartOnHomeOpenTabsTray : Event()
+
     // Interaction events with extras
 
     data class TopSiteSwipeCarousel(val page: Int) : Event() {

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

@@ -51,6 +51,7 @@ import org.mozilla.fenix.GleanMetrics.SearchSuggestions
 import org.mozilla.fenix.GleanMetrics.SearchWidget
 import org.mozilla.fenix.GleanMetrics.SetDefaultNewtabExperiment
 import org.mozilla.fenix.GleanMetrics.SetDefaultSettingExperiment
+import org.mozilla.fenix.GleanMetrics.StartOnHome
 import org.mozilla.fenix.GleanMetrics.SyncAccount
 import org.mozilla.fenix.GleanMetrics.SyncAuth
 import org.mozilla.fenix.GleanMetrics.SyncedTabs
@@ -841,6 +842,14 @@ private val Event.wrapper: EventWrapper<*>?
             { Events.browserToolbarHomeTapped.record(it) }
         )
 
+        is Event.StartOnHomeEnterHomeScreen -> EventWrapper<NoExtraKeys>(
+            { StartOnHome.enterHomeScreen.record(it) }
+        )
+
+        is Event.StartOnHomeOpenTabsTray -> EventWrapper<NoExtraKeys>(
+            { StartOnHome.openTabsTray.record(it) }
+        )
+
         // Don't record other events in Glean:
         is Event.AddBookmark -> null
         is Event.OpenedAppFirstRun -> null

app/src/main/java/org/mozilla/fenix/home/HomeFragment.kt

@@ -416,6 +416,7 @@ class HomeFragment : Fragment() {
             }
 
             view.tab_button.setOnClickListener {
+                requireComponents.analytics.metrics.track(Event.StartOnHomeOpenTabsTray)
                 openTabsTray()
             }