Make MouseTracker.sendMouseNotifications private (#41879)

* Make sendMouseNotifications private

packages/flutter/lib/src/gestures/mouse_tracking.dart

@@ -131,8 +131,8 @@ class MouseTracker extends ChangeNotifier {
   /// Stops tracking an annotation, indicating that it has been removed from the
   /// layer tree.
   ///
-  /// If the associated layer is not removed, and receives a hit, then
-  /// [sendMouseNotifications] will assert the next time it is called.
+  /// An assertion error will be thrown if the associated layer is not removed
+  /// and receives another mouse hit.
   void detachAnnotation(MouseTrackerAnnotation annotation) {
     final _TrackedAnnotation trackedAnnotation = _findAnnotation(annotation);
     for (int deviceId in trackedAnnotation.activeDevices) {
@@ -155,7 +155,7 @@ class MouseTracker extends ChangeNotifier {
     if (_trackedAnnotations.isNotEmpty && !_scheduledPostFramePositionCheck) {
       _scheduledPostFramePositionCheck = true;
       SchedulerBinding.instance.addPostFrameCallback((Duration duration) {
-        sendMouseNotifications(_lastMouseEvent.keys);
+        _sendMouseNotifications(_lastMouseEvent.keys);
         _scheduledPostFramePositionCheck = false;
       });
     }
@@ -171,14 +171,14 @@ class MouseTracker extends ChangeNotifier {
       // If we are adding the device again, then we're not removing it anymore.
       _pendingRemovals.remove(deviceId);
       _addMouseEvent(deviceId, event);
-      sendMouseNotifications(<int>{deviceId});
+      _sendMouseNotifications(<int>{deviceId});
       return;
     }
     if (event is PointerRemovedEvent) {
       _removeMouseEvent(deviceId, event);
       // If the mouse was removed, then we need to schedule one more check to
       // exit any annotations that were active.
-      sendMouseNotifications(<int>{deviceId});
+      _sendMouseNotifications(<int>{deviceId});
     } else {
       if (event is PointerMoveEvent || event is PointerHoverEvent || event is PointerDownEvent) {
         final PointerEvent lastEvent = _lastMouseEvent[deviceId];
@@ -187,7 +187,7 @@ class MouseTracker extends ChangeNotifier {
             lastEvent is PointerAddedEvent || lastEvent.position != event.position) {
           // Only schedule a frame if we have our first event, or if the
           // location of the mouse has changed, and only if there are tracked annotations.
-          sendMouseNotifications(<int>{deviceId});
+          _sendMouseNotifications(<int>{deviceId});
         }
       }
     }
@@ -212,17 +212,13 @@ class MouseTracker extends ChangeNotifier {
     return _trackedAnnotations.containsKey(annotation);
   }
 
-  /// Tells interested objects that a mouse has entered, exited, or moved, given
-  /// a callback to fetch the [MouseTrackerAnnotation] associated with a global
-  /// offset.
-  ///
-  /// This is called from a post-frame callback when the layer tree has been
-  /// updated, right after rendering the frame.
-  ///
-  /// This function is only public to allow for proper testing of the
-  /// MouseTracker. Do not call in other contexts.
-  @visibleForTesting
-  void sendMouseNotifications(Iterable<int> deviceIds) {
+  // Tells interested objects that a mouse has entered, exited, or moved, given
+  // a callback to fetch the [MouseTrackerAnnotation] associated with a global
+  // offset.
+  //
+  // This is called from a post-frame callback when the layer tree has been
+  // updated, right after rendering the frame.
+  void _sendMouseNotifications(Iterable<int> deviceIds) {
     if (_trackedAnnotations.isEmpty) {
       return;
     }

packages/flutter/test/gestures/mouse_tracking_test.dart

@@ -93,7 +93,6 @@ void main() {
       _pointerData(PointerChange.hover, const Offset(1.0, 401.0), device: 1),
     ]);
     RendererBinding.instance.mouseTracker.attachAnnotation(annotation);
-    RendererBinding.instance.mouseTracker.sendMouseNotifications(<int>{0});
     isInHitRegionOne = true;
     ui.window.onPointerDataPacket(packet1);
     expect(events, _equalToEventsOnCriticalFields(<PointerEvent>[
@@ -124,11 +123,9 @@ void main() {
     // add in a second mouse simultaneously.
     clear();
     ui.window.onPointerDataPacket(packet5);
-    RendererBinding.instance.mouseTracker.sendMouseNotifications(<int>{1});
     expect(events, _equalToEventsOnCriticalFields(<PointerEvent>[
       const PointerEnterEvent(position: Offset(1.0, 401.0), device: 1),
       const PointerHoverEvent(position: Offset(1.0, 401.0), device: 1),
-      const PointerHoverEvent(position: Offset(1.0, 401.0), device: 1),
     ]));
   });
 
@@ -142,7 +139,6 @@ void main() {
     ]);
     isInHitRegionOne = true;
     RendererBinding.instance.mouseTracker.attachAnnotation(annotation);
-    RendererBinding.instance.mouseTracker.sendMouseNotifications(<int>{0});
 
     ui.window.onPointerDataPacket(packet1);
 
@@ -196,7 +192,6 @@ void main() {
     ]);
     isInHitRegionOne = true;
     RendererBinding.instance.mouseTracker.attachAnnotation(annotation);
-    RendererBinding.instance.mouseTracker.sendMouseNotifications(<int>{0});
     ui.window.onPointerDataPacket(packet1);
     ui.window.onPointerDataPacket(packet2);
     expect(events, _equalToEventsOnCriticalFields(<PointerEvent>[
@@ -219,7 +214,6 @@ void main() {
     ]);
     isInHitRegionOne = true;
     RendererBinding.instance.mouseTracker.attachAnnotation(annotation);
-    RendererBinding.instance.mouseTracker.sendMouseNotifications(<int>{0});
     ui.window.onPointerDataPacket(packet1);
     ui.window.onPointerDataPacket(packet2);
     expect(events, _equalToEventsOnCriticalFields(<PointerEvent>[