lightbox [nfc]: Pull out VideoDurationLabel

In addition also make VideoPositionSliderControl public
for testing visibility.

Author: rajveermalviya

lib/widgets/lightbox.dart

@@ -248,18 +248,41 @@ class _ImageLightboxPageState extends State<_ImageLightboxPage> {
   }
 }
 
-class _VideoPositionSliderControl extends StatefulWidget {
+class VideoDurationLabel extends StatelessWidget {
+  const VideoDurationLabel(this.duration, {super.key});
+
+  final Duration duration;
+
+  static String _formatDuration(Duration value) {
+    final hours = value.inHours.toString().padLeft(2, '0');
+    final minutes = value.inMinutes.remainder(60).toString().padLeft(2, '0');
+    final seconds = value.inSeconds.remainder(60).toString().padLeft(2, '0');
+    return '${hours == '00' ? '' : '$hours:'}$minutes:$seconds';
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Text(_formatDuration(duration),
+      style: const TextStyle(color: Colors.white));
+  }
+}
+
+class VideoPositionSliderControl extends StatefulWidget {
   final VideoPlayerController controller;
 
-  const _VideoPositionSliderControl({
+  const VideoPositionSliderControl({
+    super.key,
     required this.controller,
   });
 
   @override
-  State<_VideoPositionSliderControl> createState() => _VideoPositionSliderControlState();
+  State<VideoPositionSliderControl> createState() => _VideoPositionSliderControlState();
+
+  @visibleForTesting
+  static final kCurrentPositionLabelKey = UniqueKey();
 }
 
-class _VideoPositionSliderControlState extends State<_VideoPositionSliderControl> {
+class _VideoPositionSliderControlState extends State<VideoPositionSliderControl> {
   Duration _sliderValue = Duration.zero;
   bool _isSliderDragging = false;
 
@@ -293,22 +316,15 @@ class _VideoPositionSliderControlState extends State<_VideoPositionSliderControl
     });
   }
 
-  static String _formatDuration(Duration value) {
-    final hours = value.inHours.toString().padLeft(2, '0');
-    final minutes = value.inMinutes.remainder(60).toString().padLeft(2, '0');
-    final seconds = value.inSeconds.remainder(60).toString().padLeft(2, '0');
-    return '${hours == '00' ? '' : '$hours:'}$minutes:$seconds';
-  }
-
   @override
   Widget build(BuildContext context) {
     final currentPosition = _isSliderDragging
       ? _sliderValue
       : widget.controller.value.position;
 
     return Row(children: [
-      Text(_formatDuration(currentPosition),
-        style: const TextStyle(color: Colors.white)),
+      VideoDurationLabel(currentPosition,
+        key: VideoPositionSliderControl.kCurrentPositionLabelKey),
       Expanded(
         child: Slider(
           value: currentPosition.inMilliseconds.toDouble(),
@@ -337,8 +353,7 @@ class _VideoPositionSliderControlState extends State<_VideoPositionSliderControl
           },
         ),
       ),
-      Text(_formatDuration(widget.controller.value.duration),
-        style: const TextStyle(color: Colors.white)),
+      VideoDurationLabel(widget.controller.value.duration),
     ]);
   }
 }
@@ -427,7 +442,7 @@ class _VideoLightboxPageState extends State<VideoLightboxPage> with PerAccountSt
       color: color,
       elevation: elevation,
       child: Column(mainAxisAlignment: MainAxisAlignment.end, children: [
-        _VideoPositionSliderControl(controller: _controller!),
+        VideoPositionSliderControl(controller: _controller!),
         IconButton(
           onPressed: () {
             if (_controller!.value.isPlaying) {