improved quick tab switcher & general tab design/logic;

packages/flutter_mozilla_components/lib/src/domain/services/gecko_event.dart

@@ -31,6 +31,7 @@ class GeckoEventService extends GeckoStateEvents {
   final _engineStateSubject = BehaviorSubject.seeded(false);
   final _tabListSubject = BehaviorSubject<List<String>>();
   final _selectedTabSubject = BehaviorSubject<String?>();
+  final _restoreCompleteSubject = BehaviorSubject.seeded(false);
 
   final _tabContentSubject = ReplaySubject<TabContentState>();
   final _historySubject = ReplaySubject<HistoryEvent>();
@@ -59,6 +60,8 @@ class GeckoEventService extends GeckoStateEvents {
   ValueStream<bool> get engineReadyStateEvents => _engineStateSubject.stream;
   ValueStream<List<String>> get tabListEvents => _tabListSubject.stream;
   ValueStream<String?> get selectedTabEvents => _selectedTabSubject.stream;
+  ValueStream<bool> get restoreCompleteEvents =>
+      _restoreCompleteSubject.stream;
 
   Stream<TabContentState> get tabContentEvents => _tabContentSubject.stream;
   Stream<HistoryEvent> get historyEvents => _historySubject.stream;
@@ -109,6 +112,11 @@ class GeckoEventService extends GeckoStateEvents {
     _selectedTabSubject.addWhenMoreRecent(sequence, id, id);
   }
 
+  @override
+  void onRestoreCompleteChange(int sequence, bool restoreComplete) {
+    _restoreCompleteSubject.addWhenMoreRecent(sequence, null, restoreComplete);
+  }
+
   @override
   void onTabContentStateChange(int sequence, TabContentState state) {
     _tabContentSubject.addWhenMoreRecent(sequence, state.id, state);

packages/flutter_mozilla_components/lib/src/domain/services/gecko_tab.dart

@@ -19,6 +19,7 @@ class GeckoTabService {
   Future<void> syncEvents({
     bool onSelectedTabChange = false,
     bool onTabListChange = false,
+    bool onRestoreComplete = false,
     bool onTabContentStateChange = false,
     bool onIconChange = false,
     bool onSecurityInfoStateChange = false,
@@ -34,6 +35,7 @@ class GeckoTabService {
     return _api.syncEvents(
       onSelectedTabChange: onSelectedTabChange,
       onTabListChange: onTabListChange,
+      onRestoreComplete: onRestoreComplete,
       onTabContentStateChange: onTabContentStateChange,
       onIconChange: onIconChange,
       onSecurityInfoStateChange: onSecurityInfoStateChange,