tab swipe to close

app/lib/features/geckoview/features/browser/presentation/widgets/tab_preview.dart

@@ -258,6 +258,7 @@ class SingleTabPreview extends HookConsumerWidget {
   final String tabId;
   final String? activeTabId;
   final String? sourceSearchQuery;
+  final double deleteThreshold;
 
   final void Function() onClose;
 
@@ -266,6 +267,7 @@ class SingleTabPreview extends HookConsumerWidget {
     required this.activeTabId,
     required this.onClose,
     required this.sourceSearchQuery,
+    this.deleteThreshold = 100,
   }) : super(key: ValueKey(tabId));
 
   @override
@@ -276,7 +278,32 @@ class SingleTabPreview extends HookConsumerWidget {
       return const SizedBox.shrink();
     }
 
-    return TabPreview(
+    final dragStartPosition = useRef(Offset.zero);
+    final draggedDistance = useState(0.0);
+
+    return GestureDetector(
+      onHorizontalDragStart: (details) {
+        dragStartPosition.value = details.globalPosition;
+        draggedDistance.value = 0.0;
+      },
+      onHorizontalDragUpdate: (details) {
+        final cappedDistance = math.min(
+          (dragStartPosition.value - details.globalPosition).dx.abs(),
+          deleteThreshold,
+        );
+
+        draggedDistance.value = cappedDistance;
+      },
+      onHorizontalDragEnd: (details) async {
+        if (draggedDistance.value >= deleteThreshold) {
+          await ref.read(tabRepositoryProvider.notifier).closeTab(tab.id);
+        }
+
+        draggedDistance.value = 0.0;
+      },
+      child: Opacity(
+        opacity: 1.0 - draggedDistance.value / deleteThreshold,
+        child: TabPreview(
           tab: tab,
           isActive: tabId == activeTabId,
           onTap: () async {
@@ -316,6 +343,8 @@ class SingleTabPreview extends HookConsumerWidget {
           onDelete: () async {
             await ref.read(tabRepositoryProvider.notifier).closeTab(tab.id);
           },
+        ),
+      ),
     );
   }
 }