Drag and drop cleans up touch sequences from the source window.

ui/events/gestures/gesture_recognizer_impl_mac.cc

Index: ui/events/gestures/gesture_recognizer_impl_mac.cc
diff --git a/ui/events/gestures/gesture_recognizer_impl_mac.cc b/ui/events/gestures/gesture_recognizer_impl_mac.cc
index f48f870058314bd6df25fc42d942145beb00ea9a..73e3cdc99cc68198836d7ab269502f7a10669561 100644
--- a/ui/events/gestures/gesture_recognizer_impl_mac.cc
+++ b/ui/events/gestures/gesture_recognizer_impl_mac.cc
@@ -41,7 +41,8 @@ class GestureRecognizerImplMac : public GestureRecognizer {
   }
   void CancelActiveTouchesExcept(GestureConsumer* not_cancelled) override {}
   void TransferEventsTo(GestureConsumer* current_consumer,
-                        GestureConsumer* new_consumer) override {}
+                        GestureConsumer* new_consumer,
+                        ShouldCancelTouches should_cancel_touches) override {}
   bool GetLastTouchPointForTarget(GestureConsumer* consumer,
                                   gfx::PointF* point) override {
     return false;