Revert "Only reject gestures to embedded UIViews when the framework says so. (#7307)" (#7313)

This reverts commit cc9c6702da5b8f0db4753c0e6a4a2002670941d6.

shell/platform/darwin/ios/framework/Source/FlutterPlatformViews.mm

@@ -29,8 +29,6 @@ void FlutterPlatformViewsController::OnMethodCall(FlutterMethodCall* call, Flutt
     OnDispose(call, result);
   } else if ([[call method] isEqualToString:@"acceptGesture"]) {
     OnAcceptGesture(call, result);
-  } else if ([[call method] isEqualToString:@"rejectGesture"]) {
-    OnRejectGesture(call, result);
   } else {
     result(FlutterMethodNotImplemented);
   }
@@ -127,24 +125,6 @@ void FlutterPlatformViewsController::OnAcceptGesture(FlutterMethodCall* call,
   result(nil);
 }
 
-void FlutterPlatformViewsController::OnRejectGesture(FlutterMethodCall* call,
-                                                     FlutterResult& result) {
-  NSDictionary<NSString*, id>* args = [call arguments];
-  int64_t viewId = [args[@"id"] longLongValue];
-
-  if (views_.count(viewId) == 0) {
-    result([FlutterError errorWithCode:@"unknown_view"
-                               message:@"trying to set gesture state for an unknown view"
-                               details:[NSString stringWithFormat:@"view id: '%lld'", viewId]]);
-    return;
-  }
-
-  FlutterTouchInterceptingView* view = touch_interceptors_[viewId].get();
-  [view blockGesture];
-
-  result(nil);
-}
-
 void FlutterPlatformViewsController::RegisterViewFactory(
     NSObject<FlutterPlatformViewFactory>* factory,
     NSString* factoryId) {
@@ -289,9 +269,6 @@ void FlutterPlatformViewsController::EnsureGLOverlayInitialized(
 // invoking an acceptGesture method on the platform_views channel). And this is how we allow the
 // Flutter framework to delay or prevent the embedded view from getting a touch sequence.
 @interface DelayingGestureRecognizer : UIGestureRecognizer <UIGestureRecognizerDelegate>
-- (instancetype)initWithTarget:(id)target
-                        action:(SEL)action
-          forwardingRecognizer:(UIGestureRecognizer*)forwardingRecognizer;
 @end
 
 // While the DelayingGestureRecognizer is preventing touches from hitting the responder chain
@@ -324,10 +301,7 @@ void FlutterPlatformViewsController::EnsureGLOverlayInitialized(
         [[[ForwardingGestureRecognizer alloc] initWithTarget:self
                                                  flutterView:flutterView] autorelease];
 
-    _delayingRecognizer.reset([[DelayingGestureRecognizer alloc]
-              initWithTarget:self
-                      action:nil
-        forwardingRecognizer:forwardingRecognizer]);
+    _delayingRecognizer.reset([[DelayingGestureRecognizer alloc] initWithTarget:self action:nil]);
 
     [self addGestureRecognizer:_delayingRecognizer.get()];
     [self addGestureRecognizer:forwardingRecognizer];
@@ -338,34 +312,21 @@ void FlutterPlatformViewsController::EnsureGLOverlayInitialized(
 - (void)releaseGesture {
   _delayingRecognizer.get().state = UIGestureRecognizerStateFailed;
 }
-
-- (void)blockGesture {
-  _delayingRecognizer.get().state = UIGestureRecognizerStateEnded;
-}
-
 @end
 
-@implementation DelayingGestureRecognizer {
-  fml::scoped_nsobject<UIGestureRecognizer> _forwardingRecognizer;
-}
-
-- (instancetype)initWithTarget:(id)target
-                        action:(SEL)action
-          forwardingRecognizer:(UIGestureRecognizer*)forwardingRecognizer {
+@implementation DelayingGestureRecognizer
+- (instancetype)initWithTarget:(id)target action:(SEL)action {
   self = [super initWithTarget:target action:action];
   if (self) {
     self.delaysTouchesBegan = YES;
     self.delegate = self;
-    _forwardingRecognizer.reset(forwardingRecognizer);
   }
   return self;
 }
 
 - (BOOL)gestureRecognizer:(UIGestureRecognizer*)gestureRecognizer
     shouldBeRequiredToFailByGestureRecognizer:(UIGestureRecognizer*)otherGestureRecognizer {
-  // The forwarding gesture recognizer should always get all touch events, so it should not be
-  // required to fail by any other gesture recognizer.
-  return otherGestureRecognizer != _forwardingRecognizer.get() && otherGestureRecognizer != self;
+  return otherGestureRecognizer != self;
 }
 
 - (BOOL)gestureRecognizer:(UIGestureRecognizer*)gestureRecognizer
@@ -373,12 +334,21 @@ void FlutterPlatformViewsController::EnsureGLOverlayInitialized(
   return otherGestureRecognizer == self;
 }
 
-- (void)touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event {
-  self.state = UIGestureRecognizerStateBegan;
+- (void)touchesEnded:(NSSet*)touches withEvent:(UIEvent*)event {
+  // The gesture has ended, and the delaying gesture recognizer was not failed, we recognize
+  // the gesture to prevent the touches from being dispatched to the embedded view.
+  //
+  // This doesn't work well with gestures that are recognized by the Flutter framework after
+  // all pointers are up.
+  //
+  // TODO(amirh): explore if we can instead set this to recognized when the next touch sequence
+  //  begins, or we can use a framework signal for restarting the recognizers (e.g when the
+  //  gesture arena is resolved).
+  self.state = UIGestureRecognizerStateRecognized;
 }
 
 - (void)touchesCancelled:(NSSet*)touches withEvent:(UIEvent*)event {
-  self.state = UIGestureRecognizerStateCancelled;
+  self.state = UIGestureRecognizerStateRecognized;
 }
 @end
 
@@ -410,12 +380,12 @@ void FlutterPlatformViewsController::EnsureGLOverlayInitialized(
 
 - (void)touchesEnded:(NSSet*)touches withEvent:(UIEvent*)event {
   [_flutterView touchesEnded:touches withEvent:event];
-  self.state = UIGestureRecognizerStateEnded;
+  self.state = UIGestureRecognizerStateRecognized;
 }
 
 - (void)touchesCancelled:(NSSet*)touches withEvent:(UIEvent*)event {
   [_flutterView touchesCancelled:touches withEvent:event];
-  self.state = UIGestureRecognizerStateCancelled;
+  self.state = UIGestureRecognizerStateRecognized;
 }
 
 - (BOOL)gestureRecognizer:(UIGestureRecognizer*)gestureRecognizer

shell/platform/darwin/ios/framework/Source/FlutterPlatformViews_Internal.h

@@ -22,9 +22,6 @@
 
 // Stop delaying any active touch sequence (and let it arrive the embedded view).
 - (void)releaseGesture;
-
-// Prevent the touch sequence from ever arriving to the embedded view.
-- (void)blockGesture;
 @end
 
 namespace shell {
@@ -92,7 +89,6 @@ class FlutterPlatformViewsController {
   void OnCreate(FlutterMethodCall* call, FlutterResult& result);
   void OnDispose(FlutterMethodCall* call, FlutterResult& result);
   void OnAcceptGesture(FlutterMethodCall* call, FlutterResult& result);
-  void OnRejectGesture(FlutterMethodCall* call, FlutterResult& result);
 
   void EnsureOverlayInitialized(int64_t overlay_id);
   void EnsureGLOverlayInitialized(int64_t overlay_id,