Always send the ET_GESTURE_END event as the last one for every touch

event.

Occasionally we synthesize scroll or tap cancel events when a touch
sequence has been canceled or terminated, we want to make sure that
ET_GESTURE_END always happens after them.

BUG=379772

Review URL: https://codereview.chromium.org/549333002

Cr-Commit-Position: refs/heads/master@{#294010}

ui/events/gesture_detection/touch_disposition_gesture_filter.cc

@@ -219,7 +219,7 @@ void TouchDispositionGestureFilter::FilterAndSendPacket(
   } else if (packet.gesture_source() == GestureEventDataPacket::TOUCH_START) {
     CancelTapIfNecessary(packet);
   }
-
+  int gesture_end_index = -1;
   for (size_t i = 0; i < packet.gesture_count(); ++i) {
     const GestureEventData& gesture = packet.gesture(i);
     DCHECK_GE(gesture.details.type(), ET_GESTURE_TYPE_START);
@@ -232,9 +232,20 @@ void TouchDispositionGestureFilter::FilterAndSendPacket(
       // Sending a timed gesture could delete |this|, so we need to return
       // directly after the |SendGesture| call.
       SendGesture(gesture, packet);
+      // We should not have a timeout gesture and other gestures in the same
+      // packet.
+      DCHECK_EQ(1U, packet.gesture_count());
       return;
     }
-
+    // Occasionally scroll or tap cancel events are synthesized when a touch
+    // sequence has been canceled or terminated, we want to make sure that
+    // ET_GESTURE_END always happens after them.
+    if (gesture.type() == ET_GESTURE_END) {
+      // Make sure there is at most one ET_GESTURE_END event in each packet.
+      DCHECK_EQ(-1, gesture_end_index);
+      gesture_end_index = static_cast<int>(i);
+      continue;
+    }
     SendGesture(gesture, packet);
   }
 
@@ -246,6 +257,9 @@ void TouchDispositionGestureFilter::FilterAndSendPacket(
              GestureEventDataPacket::TOUCH_SEQUENCE_END) {
     EndScrollIfNecessary(packet);
   }
+  // Always send the ET_GESTURE_END event as the last one for every touch event.
+  if (gesture_end_index >= 0)
+    SendGesture(packet.gesture(gesture_end_index), packet);
 }
 
 void TouchDispositionGestureFilter::SendGesture(

ui/events/gesture_detection/touch_disposition_gesture_filter_unittest.cc

@@ -988,7 +988,7 @@ TEST_F(TouchDispositionGestureFilterTest,
   PushGesture(ET_GESTURE_END);
   ReleaseTouchPoint();
   SendTouchNotConsumedAck();
-  EXPECT_TRUE(GesturesMatch(Gestures(ET_GESTURE_END, ET_GESTURE_SCROLL_END),
+  EXPECT_TRUE(GesturesMatch(Gestures(ET_GESTURE_SCROLL_END, ET_GESTURE_END),
                             GetAndResetSentGestures()));
   EXPECT_EQ(LastSentGestureLocation(), gfx::PointF(2, 2));
 
@@ -1101,4 +1101,25 @@ TEST_F(TouchDispositionGestureFilterTest, ShowPressBoundingBox) {
   EXPECT_EQ(gfx::RectF(5, 5, 10, 10), ShowPressBoundingBox());
 }
 
+TEST_F(TouchDispositionGestureFilterTest, TapCancelledBeforeGestureEnd) {
+  PushGesture(ET_GESTURE_BEGIN);
+  PushGesture(ET_GESTURE_TAP_DOWN);
+  PressTouchPoint(1, 1);
+  SendTouchNotConsumedAck();
+  EXPECT_TRUE(GesturesMatch(Gestures(ET_GESTURE_BEGIN, ET_GESTURE_TAP_DOWN),
+                            GetAndResetSentGestures()));
+  SendTimeoutGesture(ET_GESTURE_SHOW_PRESS);
+  EXPECT_TRUE(GesturesMatch(Gestures(ET_GESTURE_SHOW_PRESS),
+                            GetAndResetSentGestures()));
+
+  SendTimeoutGesture(ET_GESTURE_LONG_PRESS);
+  EXPECT_TRUE(GesturesMatch(Gestures(ET_GESTURE_LONG_PRESS),
+                            GetAndResetSentGestures()));
+  PushGesture(ET_GESTURE_END);
+  CancelTouchPoint();
+  SendTouchNotConsumedAck();
+  EXPECT_TRUE(GesturesMatch(Gestures(ET_GESTURE_TAP_CANCEL, ET_GESTURE_END),
+                            GetAndResetSentGestures()));
+}
+
 }  // namespace ui