[macOS] Handle interleaved movement and gesture events

shell/platform/darwin/macos/framework/Source/FlutterViewController.mm

@@ -129,7 +129,6 @@ void Reset() {
     flutter_state_is_down = false;
     has_pending_exit = false;
     buttons = 0;
-    GestureReset();
   }
 };
 

shell/platform/darwin/macos/framework/Source/FlutterViewControllerTest.mm

@@ -101,6 +101,7 @@ - (bool)testKeyEquivalentIsPassedToTextInputPlugin:(id)mockEngine;
 - (bool)testFlagsChangedEventsArePropagatedIfNotHandled:(id)mockEngine;
 - (bool)testKeyboardIsRestartedOnEngineRestart:(id)mockEngine;
 - (bool)testTrackpadGesturesAreSentToFramework:(id)mockEngine;
+- (bool)mouseAndGestureEventsAreHandledSeparately:(id)engineMock;
 - (bool)testMouseDownUpEventsSentToNextResponder:(id)mockEngine;
 - (bool)testModifierKeysAreSynthesizedOnMouseMove:(id)mockEngine;
 - (bool)testViewWillAppearCalledMultipleTimes:(id)mockEngine;
@@ -287,6 +288,12 @@ id MockGestureEvent(NSEventType type, NSEventPhase phase, double magnification,
       [[FlutterViewControllerTestObjC alloc] testTrackpadGesturesAreSentToFramework:mockEngine]);
 }
 
+TEST_F(FlutterViewControllerMockEngineTest, TestmouseAndGestureEventsAreHandledSeparately) {
+  id mockEngine = GetMockEngine();
+  ASSERT_TRUE(
+      [[FlutterViewControllerTestObjC alloc] mouseAndGestureEventsAreHandledSeparately:mockEngine]);
+}
+
 TEST_F(FlutterViewControllerMockEngineTest, TestMouseDownUpEventsSentToNextResponder) {
   id mockEngine = GetMockEngine();
   ASSERT_TRUE(
@@ -1004,6 +1011,42 @@ - (bool)testTrackpadGesturesAreSentToFramework:(id)engineMock {
   return true;
 }
 
+// Magic mouse can interleave mouse events with scroll events. This must not crash.
+- (bool)mouseAndGestureEventsAreHandledSeparately:(id)engineMock {
+  FlutterViewController* viewController = [[FlutterViewController alloc] initWithEngine:engineMock
+                                                                                nibName:@""
+                                                                                 bundle:nil];
+  [viewController loadView];
+
+  // Test for pan events.
+  // Start gesture.
+  CGEventRef cgEventStart = CGEventCreateScrollWheelEvent(NULL, kCGScrollEventUnitPixel, 1, 0);
+  CGEventSetType(cgEventStart, kCGEventScrollWheel);
+  CGEventSetIntegerValueField(cgEventStart, kCGScrollWheelEventScrollPhase, kCGScrollPhaseBegan);
+  CGEventSetIntegerValueField(cgEventStart, kCGScrollWheelEventIsContinuous, 1);
+  [viewController scrollWheel:[NSEvent eventWithCGEvent:cgEventStart]];
+  CFRelease(cgEventStart);
+
+  CGEventRef cgEventUpdate = CGEventCreateCopy(cgEventStart);
+  CGEventSetIntegerValueField(cgEventUpdate, kCGScrollWheelEventScrollPhase, kCGScrollPhaseChanged);
+  CGEventSetIntegerValueField(cgEventUpdate, kCGScrollWheelEventDeltaAxis2, 1);  // pan_x
+  CGEventSetIntegerValueField(cgEventUpdate, kCGScrollWheelEventDeltaAxis1, 2);  // pan_y
+  [viewController scrollWheel:[NSEvent eventWithCGEvent:cgEventUpdate]];
+  CFRelease(cgEventUpdate);
+
+  NSEvent* mouseEvent = flutter::testing::CreateMouseEvent(0x00);
+  [viewController mouseEntered:mouseEvent];
+  [viewController mouseExited:mouseEvent];
+
+  // End gesture.
+  CGEventRef cgEventEnd = CGEventCreateCopy(cgEventStart);
+  CGEventSetIntegerValueField(cgEventEnd, kCGScrollWheelEventScrollPhase, kCGScrollPhaseEnded);
+  [viewController scrollWheel:[NSEvent eventWithCGEvent:cgEventEnd]];
+  CFRelease(cgEventEnd);
+
+  return true;
+}
+
 - (bool)testViewWillAppearCalledMultipleTimes:(id)engineMock {
   FlutterViewController* viewController = [[FlutterViewController alloc] initWithEngine:engineMock
                                                                                 nibName:@""