ozone: Cancel all touches once a single touch is cancelled

ui/events/ozone/evdev/touch_event_converter_evdev.cc

Index: ui/events/ozone/evdev/touch_event_converter_evdev.cc
diff --git a/ui/events/ozone/evdev/touch_event_converter_evdev.cc b/ui/events/ozone/evdev/touch_event_converter_evdev.cc
index c46608d938577b8a3ec79c290e71ab7be7ddf89b..71dc635efba77c57ce04c9d4c09d3b74fbefaef9 100644
--- a/ui/events/ozone/evdev/touch_event_converter_evdev.cc
+++ b/ui/events/ozone/evdev/touch_event_converter_evdev.cc
@@ -188,7 +188,9 @@ void TouchEventConverterEvdev::Initialize(const EventDeviceInfo& info) {
           info.GetAbsMtSlotValueWithDefault(ABS_MT_TOUCH_MINOR, i, 0) / 2.0f;
       events_[i].pressure = ScalePressure(
           info.GetAbsMtSlotValueWithDefault(ABS_MT_PRESSURE, i, 0));
-      events_[i].cancelled = (major_max_ > 0 && touch_major == major_max_);
+      if (major_max_ > 0 && touch_major == major_max_) {
+        CancelAllTouches();

[spang, 2017/01/19 01:25:51]

Can this move after the loop so it runs at most once?

After this change Initialize() will never set |cancelled| to false. Is that
intended?

[denniskempin, 2017/01/20 02:04:39]

Done.

+      }
     }
   } else {
     // TODO(spang): Add key state to EventDeviceInfo to allow initial contact.
@@ -371,8 +373,9 @@ void TouchEventConverterEvdev::ProcessAbs(const input_event& input) {
 
       // The MT protocol cannot communicate cancelled touches, so some kernel
       // drivers will identify palms by setting touch major to max.
-      if (major_max_ > 0 && input.value == major_max_)
-        events_[current_slot_].cancelled = true;
+      if (major_max_ > 0 && input.value == major_max_) {
+        CancelAllTouches();

[spang, 2017/01/19 01:25:51]

What if we get a new contact with a lower numbered slot before the syn_report ?
Such a press will be reordered before all of the cancels and will still be alive
despite the attempt to cancel everything.

We really shouldn't to do anything here other than update events_[current_slot_]
to match our view the kernel internal state.

[denniskempin, 2017/01/20 02:04:39]

Done.

+      }
       break;
     case ABS_MT_TOUCH_MINOR:
       events_[current_slot_].radius_y = input.value / 2.0f;
@@ -445,14 +448,31 @@ void TouchEventConverterEvdev::ReportTouchEvent(
                        gfx::PointF(event.x, event.y), details, timestamp));
 }
 
+void TouchEventConverterEvdev::CancelAllTouches() {
+  for (size_t i = 0; i < events_.size(); i++) {
+    InProgressTouchEvdev* event = &events_[i];
+    if (event->was_touching || event->touching) {
+      event->cancelled = true;
+      event->altered = true;
+    }
+  }
+}
+
 void TouchEventConverterEvdev::ReportEvents(base::TimeTicks timestamp) {
   if (dropped_events_) {
     Reinitialize();
     dropped_events_ = false;
   }
 
-  if (touch_noise_finder_)
+  if (touch_noise_finder_) {
     touch_noise_finder_->HandleTouches(events_, timestamp);
+    for (size_t i = 0; i < events_.size(); i++) {
+      if (touch_noise_finder_->SlotHasNoise(events_[i].slot)) {
+        CancelAllTouches();
+        break;
+      }
+    }
+  }
 
   for (size_t i = 0; i < events_.size(); i++) {
     InProgressTouchEvdev* event = &events_[i];
@@ -462,9 +482,6 @@ void TouchEventConverterEvdev::ReportEvents(base::TimeTicks timestamp) {
     if (enable_palm_suppression_callback_)
       enable_palm_suppression_callback_.Run(event->tool_code > 0);
 
-    if (touch_noise_finder_ && touch_noise_finder_->SlotHasNoise(event->slot))
-      event->cancelled = true;
-
     EventType event_type = GetEventTypeForTouch(*event);
     // The tool type is fixed with the touch pressed event and does not change.
     if (event_type == ET_TOUCH_PRESSED)