For #2785 - Adds back item animator session control (#3233)

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

@@ -128,7 +128,14 @@ class HomeFragment : Fragment(), CoroutineScope, AccountObserver {
                 this,
                 SessionControlViewModel::class.java
             ) {
-                SessionControlViewModel(SessionControlState(listOf(), setOf(), listOf(), mode))
+                SessionControlViewModel(
+                    SessionControlState(
+                        getListOfTabs(requireComponents.core.sessionManager),
+                        setOf(),
+                        requireComponents.core.tabCollectionStorage.cachedTabCollections,
+                        mode
+                    )
+                )
             }
         )
 
@@ -269,10 +276,14 @@ class HomeFragment : Fragment(), CoroutineScope, AccountObserver {
                 }
         }
 
-        val mode = currentMode()
+        getManagedEmitter<SessionControlChange>().onNext(
-        getManagedEmitter<SessionControlChange>().onNext(SessionControlChange.ModeChange(mode))
+            SessionControlChange.Change(
+                tabs = getListOfTabs(sessionManager = requireComponents.core.sessionManager),
+                mode = currentMode(),
+                collections = requireComponents.core.tabCollectionStorage.cachedTabCollections
+            )
+        )
 
-        emitSessionChanges()
         sessionObserver.onStart()
         tabCollectionObserver = subscribeToTabCollections()
     }
@@ -609,27 +620,30 @@ class HomeFragment : Fragment(), CoroutineScope, AccountObserver {
     }
 
     private fun emitSessionChanges() {
-        val sessionManager = requireComponents.core.sessionManager
+        val sessionManager = context?.components?.core?.sessionManager ?: return
-
         getManagedEmitter<SessionControlChange>().onNext(
             SessionControlChange.TabsChange(
-                sessionManager.sessions
+                getListOfTabs(sessionManager)
-                    .filter { (activity as HomeActivity).browsingModeManager.isPrivate == it.private }
-                    .map {
-                        val selected = it == sessionManager.selectedSession
-                        Tab(
-                            it.id,
-                            it.url,
-                            it.url.urlToTrimmedHost(),
-                            it.title,
-                            selected,
-                            it.thumbnail
-                        )
-                    }
             )
         )
     }
 
+    private fun getListOfTabs(sessionManager: SessionManager): List<Tab> {
+        return sessionManager.sessions
+            .filter { (activity as HomeActivity).browsingModeManager.isPrivate == it.private }
+            .map {
+                val selected = it == sessionManager.selectedSession
+                Tab(
+                    it.id,
+                    it.url,
+                    it.url.urlToTrimmedHost(),
+                    it.title,
+                    selected,
+                    it.thumbnail
+                )
+            }
+    }
+
     private fun emitAccountChanges() {
         val mode = currentMode()
         getManagedEmitter<SessionControlChange>().onNext(SessionControlChange.ModeChange(mode))

app/src/main/java/org/mozilla/fenix/home/sessioncontrol/SessionControlComponent.kt

@@ -139,6 +139,8 @@ fun Observer<SessionControlAction>.onNext(onboardingAction: OnboardingAction) {
 }
 
 sealed class SessionControlChange : Change {
+    data class Change(val tabs: List<Tab>, val mode: Mode, val collections: List<TabCollection>) :
+        SessionControlChange()
     data class TabsChange(val tabs: List<Tab>) : SessionControlChange()
     data class ModeChange(val mode: Mode) : SessionControlChange()
     data class CollectionsChange(val collections: List<TabCollection>) : SessionControlChange()
@@ -165,6 +167,11 @@ class SessionControlViewModel(
 
                     state.copy(expandedCollections = newExpandedCollection)
                 }
+                is SessionControlChange.Change -> state.copy(
+                    tabs = change.tabs,
+                    mode = change.mode,
+                    collections = change.collections
+                )
             }
         }
     }

app/src/main/java/org/mozilla/fenix/home/sessioncontrol/SessionControlUIView.kt

@@ -139,7 +139,6 @@ class SessionControlUIView(
         view.apply {
             adapter = sessionControlAdapter
             layoutManager = LinearLayoutManager(container.context)
-            itemAnimator = null // TODO #2785: Remove this line
             val itemTouchHelper =
                 ItemTouchHelper(
                     SwipeToDeleteCallback(