Reuse a TimelineTask for the scheduler frame and animate events (#90168)

dev/tracing_tests/test/image_cache_tracing_test.dart

@@ -55,7 +55,7 @@ void main() {
         },
         <String, dynamic>{
           'name': 'listener',
-          'args': <String, dynamic>{'parentId': '0', 'isolateId': isolateId}
+          'args': <String, dynamic>{'isolateId': isolateId}
         },
         <String, dynamic>{
           'name': 'ImageCache.clear',

packages/flutter/lib/src/scheduler/binding.dart

@@ -996,8 +996,7 @@ mixin SchedulerBinding on BindingBase {
     handleDrawFrame();
   }
 
-  TimelineTask? _frameTimelineTask;
-  TimelineTask? _animateTimelineTask;
+  final TimelineTask? _frameTimelineTask = kReleaseMode ? null : TimelineTask();
 
   /// Called by the engine to prepare the framework to produce a new frame.
   ///
@@ -1023,7 +1022,7 @@ mixin SchedulerBinding on BindingBase {
   /// statements printed during a frame from those printed between frames (e.g.
   /// in response to events or timers).
   void handleBeginFrame(Duration? rawTimeStamp) {
-    _frameTimelineTask = TimelineTask()..start('Frame', arguments: timelineArgumentsIndicatingLandmarkEvent);
+    _frameTimelineTask?.start('Frame', arguments: timelineArgumentsIndicatingLandmarkEvent);
     _firstRawTimeStampInEpoch ??= rawTimeStamp;
     _currentFrameTimeStamp = _adjustForEpoch(rawTimeStamp ?? _lastRawTimeStamp);
     if (rawTimeStamp != null)
@@ -1050,7 +1049,7 @@ mixin SchedulerBinding on BindingBase {
     _hasScheduledFrame = false;
     try {
       // TRANSIENT FRAME CALLBACKS
-      _animateTimelineTask = TimelineTask()..start('Animate', arguments: timelineArgumentsIndicatingLandmarkEvent);
+      _frameTimelineTask?.start('Animate', arguments: timelineArgumentsIndicatingLandmarkEvent);
       _schedulerPhase = SchedulerPhase.transientCallbacks;
       final Map<int, _FrameCallbackEntry> callbacks = _transientCallbacks;
       _transientCallbacks = <int, _FrameCallbackEntry>{};
@@ -1075,8 +1074,7 @@ mixin SchedulerBinding on BindingBase {
   /// useful when working with frame callbacks.
   void handleDrawFrame() {
     assert(_schedulerPhase == SchedulerPhase.midFrameMicrotasks);
-    _animateTimelineTask?.finish(); // end the "Animate" phase
-    _animateTimelineTask = null;
+    _frameTimelineTask?.finish(); // end the "Animate" phase
     try {
       // PERSISTENT FRAME CALLBACKS
       _schedulerPhase = SchedulerPhase.persistentCallbacks;
@@ -1093,7 +1091,6 @@ mixin SchedulerBinding on BindingBase {
     } finally {
       _schedulerPhase = SchedulerPhase.idle;
       _frameTimelineTask?.finish(); // end the Frame
-      _frameTimelineTask = null;
       assert(() {
         if (debugPrintEndFrameBanner)
           debugPrint('▀' * _debugBanner!.length);