Suppress firing JS events for pointercancel events with non-existent

ids.

We encountered a device that reserves three-finger touches for a
system-defined gesture, so it cancels all touch points at the moment the
third finger touches the screen.  But the device wrongly sends a
pointercancel for the third finger without sending a corresponding
pointerdown first.  This caused Blink to fire a pointercancel with a new
id, which is not a valid event sequence!

This CL suppresses such pointercancel events.

Bug: 1007164
Change-Id: I0af68ac229e56344ee013a8e65fe18b3cc4e9fd7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2488181
Commit-Queue: Mustaq Ahmed <mustaq@chromium.org>
Reviewed-by: Robert Flack <flackr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#821329}

third_party/blink/renderer/core/events/pointer_event_factory.cc

@@ -222,6 +222,7 @@ PointerEventInit* PointerEventFactory::ConvertIdTypeButtonsEvent(
     const WebPointerEvent& web_pointer_event) {
   WebPointerProperties::PointerType pointer_type =
       web_pointer_event.pointer_type;
+
   unsigned buttons;
   if (web_pointer_event.hovering) {
     buttons = MouseEvent::WebInputEventModifiersToButtons(
@@ -248,12 +249,16 @@ PointerEventInit* PointerEventFactory::ConvertIdTypeButtonsEvent(
     }
     pointer_type = WebPointerProperties::PointerType::kPen;
   }
-  PointerEventInit* pointer_event_init = PointerEventInit::Create();
-  pointer_event_init->setButtons(buttons);
 
   const IncomingId incoming_id(pointer_type, web_pointer_event.id);
   PointerId pointer_id = AddIdAndActiveButtons(incoming_id, buttons != 0,
-                                               web_pointer_event.hovering);
+                                               web_pointer_event.hovering,
+                                               web_pointer_event.GetType());
+  if (pointer_id == kInvalidId)
+    return nullptr;
+
+  PointerEventInit* pointer_event_init = PointerEventInit::Create();
+  pointer_event_init->setButtons(buttons);
   pointer_event_init->setPointerId(pointer_id);
   pointer_event_init->setPointerType(
       PointerTypeNameForWebPointPointerType(pointer_type));
@@ -293,6 +298,8 @@ PointerEvent* PointerEventFactory::Create(
 
   PointerEventInit* pointer_event_init =
       ConvertIdTypeButtonsEvent(web_pointer_event);
+  if (!pointer_event_init)
+    return nullptr;
 
   AtomicString type = PointerEventNameForEventType(event_type);
   if (event_type == WebInputEvent::Type::kPointerDown ||
@@ -491,7 +498,7 @@ PointerEventFactory::~PointerEventFactory() {
 void PointerEventFactory::Clear() {
   for (int type = 0;
        type <= ToInt(WebPointerProperties::PointerType::kMaxValue); type++) {
-    primary_id_[type] = PointerEventFactory::kInvalidId;
+    primary_id_[type] = kInvalidId;
     id_count_[type] = 0;
   }
   pointer_incoming_id_mapping_.clear();
@@ -510,9 +517,11 @@ void PointerEventFactory::Clear() {
   current_id_ = PointerEventFactory::kMouseId + 1;
 }
 
-PointerId PointerEventFactory::AddIdAndActiveButtons(const IncomingId p,
+PointerId PointerEventFactory::AddIdAndActiveButtons(
+    const IncomingId p,
     bool is_active_buttons,
-                                                     bool hovering) {
+    bool hovering,
+    WebInputEvent::Type event_type) {
   // Do not add extra mouse pointer as it was added in initialization.
   if (p.GetPointerType() == WebPointerProperties::PointerType::kMouse) {
     pointer_id_mapping_.Set(kMouseId,
@@ -526,6 +535,12 @@ PointerId PointerEventFactory::AddIdAndActiveButtons(const IncomingId p,
                             PointerAttributes(p, is_active_buttons, hovering));
     return mapped_id;
   }
+
+  // TODO(crbug.com/1141595): We should filter out bad pointercancel events
+  // further upstream.
+  if (event_type == WebInputEvent::Type::kPointerCancel)
+    return kInvalidId;
+
   int type_int = p.PointerTypeInt();
   // We do not handle the overflow of |current_id_| as it should be very rare.
   PointerId mapped_id = current_id_++;
@@ -549,7 +564,7 @@ bool PointerEventFactory::Remove(const PointerId mapped_id) {
   pointer_incoming_id_mapping_.erase(p);
   RemoveLastPosition(mapped_id);
   if (primary_id_[type_int] == mapped_id)
-    primary_id_[type_int] = PointerEventFactory::kInvalidId;
+    primary_id_[type_int] = kInvalidId;
   id_count_[type_int]--;
   return true;
 }
@@ -594,8 +609,7 @@ bool PointerEventFactory::IsPrimary(
     return true;
 
   PointerId pointer_id = GetPointerEventId(properties);
-  return (pointer_id != PointerEventFactory::kInvalidId &&
-          IsPrimary(pointer_id));
+  return (pointer_id != kInvalidId && IsPrimary(pointer_id));
 }
 
 bool PointerEventFactory::IsActiveButtonsState(
@@ -618,7 +632,7 @@ PointerId PointerEventFactory::GetPointerEventId(
   IncomingId id(properties.pointer_type, properties.id);
   if (pointer_incoming_id_mapping_.Contains(id))
     return pointer_incoming_id_mapping_.at(id);
-  return PointerEventFactory::kInvalidId;
+  return kInvalidId;
 }
 
 }  // namespace blink

third_party/blink/renderer/core/events/pointer_event_factory.h

@@ -30,6 +30,8 @@ class CORE_EXPORT PointerEventFactory {
   PointerEventFactory();
   ~PointerEventFactory();
 
+  // Returns nullptr if the |web_pointer_event| is invalid from event stream
+  // perspective (e.g. it is a pointercancel for a non-existent id).
   PointerEvent* Create(const WebPointerEvent& web_pointer_event,
                        const Vector<WebPointerEvent>& coalesced_events,
                        const Vector<WebPointerEvent>& predicted_events,
@@ -128,9 +130,14 @@ class CORE_EXPORT PointerEventFactory {
 
   PointerId AddIdAndActiveButtons(const IncomingId,
                                   bool is_active_buttons,
-                                  bool hovering);
+                                  bool hovering,
+                                  WebInputEvent::Type event_type);
   bool IsPrimary(const PointerId) const;
+
+  // Returns nullptr when the event is unexpected.  E.g. pointercancel for a
+  // non-existent id (see crbug.com/1007164).
   PointerEventInit* ConvertIdTypeButtonsEvent(const WebPointerEvent&);
+
   void SetEventSpecificFields(PointerEventInit*, const AtomicString& type);
 
   // Creates pointerevents like boundary and capture events from another

third_party/blink/renderer/core/input/pointer_event_manager.cc

@@ -463,8 +463,12 @@ WebInputEventResult PointerEventManager::DispatchTouchPointerEvent(
             ? pointer_event_target.target_element->GetDocument().domWindow()
             : nullptr);
 
+    if (pointer_event) {
       result = SendTouchPointerEvent(pointer_event_target.target_element,
                                      pointer_event, web_pointer_event.hovering);
+    } else {
+      result = WebInputEventResult::kNotHandled;
+    }
 
     // If a pointerdown has been canceled, queue the unique id to allow
     // suppressing mouse events from gesture events. For mouse events

third_party/blink/renderer/core/input/pointer_event_manager_test.cc

@@ -22,23 +22,29 @@ namespace {
 class CheckPointerEventListenerCallback final : public NativeEventListener {
  public:
   void Invoke(ExecutionContext*, Event* event) override {
-    const String pointer_type = ((PointerEvent*)event)->pointerType();
+    num_events_received_++;
+
+    const String pointer_type =
+        static_cast<PointerEvent*>(event)->pointerType();
     if (pointer_type == "mouse")
-      mouse_event_received_count_++;
+      num_type_mouse_received_++;
     else if (pointer_type == "touch")
-      touch_event_received_count_++;
+      num_type_touch_received_++;
     else if (pointer_type == "pen")
-      pen_event_received_count_++;
+      num_type_pen_received_++;
   }
 
-  int mouseEventCount() const { return mouse_event_received_count_; }
-  int touchEventCount() const { return touch_event_received_count_; }
-  int penEventCount() const { return pen_event_received_count_; }
+  int numEventsReceived() const { return num_events_received_; }
+
+  int numTypeMouseReceived() const { return num_type_mouse_received_; }
+  int numTypeTouchReceived() const { return num_type_touch_received_; }
+  int numTypePenReceived() const { return num_type_pen_received_; }
 
  private:
-  int mouse_event_received_count_ = 0;
-  int touch_event_received_count_ = 0;
-  int pen_event_received_count_ = 0;
+  int num_events_received_ = 0;
+  int num_type_mouse_received_ = 0;
+  int num_type_touch_received_ = 0;
+  int num_type_pen_received_ = 0;
 };
 
 class PointerEventCoordinateListenerCallback final
@@ -49,7 +55,7 @@ class PointerEventCoordinateListenerCallback final
   }
 
   void Invoke(ExecutionContext*, Event* event) override {
-    const PointerEvent* pointer_event = (PointerEvent*)event;
+    const PointerEvent* pointer_event = static_cast<PointerEvent*>(event);
     last_client_x_ = pointer_event->clientX();
     last_client_y_ = pointer_event->clientY();
     last_page_x_ = pointer_event->pageX();
@@ -84,17 +90,21 @@ class PointerEventManagerTest : public SimTest {
   std::unique_ptr<WebPointerEvent> CreateTestPointerEvent(
       WebInputEvent::Type type,
       WebPointerProperties::PointerType pointer_type,
-      gfx::PointF position_in_widget = gfx::PointF(100, 100),
-      gfx::PointF position_in_screen = gfx::PointF(100, 100),
-      int movement_x = 0,
-      int movement_y = 0,
+      PointerId id = 1) {
+    return CreateTestPointerEvent(type, pointer_type, id, gfx::PointF(100, 100),
+                                  gfx::PointF(100, 100), 0, 0, 1, 1);
+  }
+  std::unique_ptr<WebPointerEvent> CreateTestPointerEvent(
+      WebInputEvent::Type type,
+      WebPointerProperties::PointerType pointer_type,
+      gfx::PointF position_in_widget,
+      gfx::PointF position_in_screen,
+      int movement_x,
+      int movement_y,
       float width = 1,
       float height = 1) {
-    return std::make_unique<WebPointerEvent>(
-        type,
-        WebPointerProperties(
-            1, pointer_type, WebPointerProperties::Button::kLeft,
-            position_in_widget, position_in_screen, movement_x, movement_y),
+    return CreateTestPointerEvent(type, pointer_type, 1, position_in_widget,
+                                  position_in_screen, movement_x, movement_y,
                                   width, height);
   }
   WebMouseEvent CreateTestMouseEvent(WebInputEvent::Type type,
@@ -106,6 +116,25 @@ class PointerEventManagerTest : public SimTest {
     event.SetFrameScale(1);
     return event;
   }
+
+ private:
+  std::unique_ptr<WebPointerEvent> CreateTestPointerEvent(
+      WebInputEvent::Type type,
+      WebPointerProperties::PointerType pointer_type,
+      PointerId id,
+      gfx::PointF position_in_widget,
+      gfx::PointF position_in_screen,
+      int movement_x,
+      int movement_y,
+      float width,
+      float height) {
+    return std::make_unique<WebPointerEvent>(
+        type,
+        WebPointerProperties(
+            id, pointer_type, WebPointerProperties::Button::kLeft,
+            position_in_widget, position_in_screen, movement_x, movement_y),
+        width, height);
+  }
 };
 
 TEST_F(PointerEventManagerTest, HasPointerCapture) {
@@ -175,34 +204,75 @@ TEST_F(PointerEventManagerTest, PointerCancelsOfAllTypes) {
   GetEventHandler().HandleMousePressEvent(CreateTestMouseEvent(
       WebInputEvent::Type::kMouseDown, gfx::PointF(100, 100)));
 
-  ASSERT_EQ(callback->mouseEventCount(), 0);
-  ASSERT_EQ(callback->touchEventCount(), 0);
-  ASSERT_EQ(callback->penEventCount(), 0);
+  ASSERT_EQ(callback->numTypeMouseReceived(), 0);
+  ASSERT_EQ(callback->numTypeTouchReceived(), 0);
+  ASSERT_EQ(callback->numTypePenReceived(), 0);
 
   WebView().MainFrameWidget()->HandleInputEvent(WebCoalescedInputEvent(
       CreateTestPointerEvent(WebInputEvent::Type::kPointerCausedUaAction,
                              WebPointerProperties::PointerType::kPen),
       {}, {}, ui::LatencyInfo()));
-  ASSERT_EQ(callback->mouseEventCount(), 0);
-  ASSERT_EQ(callback->touchEventCount(), 1);
-  ASSERT_EQ(callback->penEventCount(), 1);
+  ASSERT_EQ(callback->numTypeMouseReceived(), 0);
+  ASSERT_EQ(callback->numTypeTouchReceived(), 1);
+  ASSERT_EQ(callback->numTypePenReceived(), 1);
 
   WebView().MainFrameWidget()->HandleInputEvent(WebCoalescedInputEvent(
       CreateTestPointerEvent(WebInputEvent::Type::kPointerCausedUaAction,
                              WebPointerProperties::PointerType::kTouch),
       {}, {}, ui::LatencyInfo()));
-  ASSERT_EQ(callback->mouseEventCount(), 0);
-  ASSERT_EQ(callback->touchEventCount(), 1);
-  ASSERT_EQ(callback->penEventCount(), 1);
+  ASSERT_EQ(callback->numTypeMouseReceived(), 0);
+  ASSERT_EQ(callback->numTypeTouchReceived(), 1);
+  ASSERT_EQ(callback->numTypePenReceived(), 1);
 
   GetEventHandler().HandleMouseMoveEvent(
       CreateTestMouseEvent(WebInputEvent::Type::kMouseMove,
                            gfx::PointF(200, 200)),
       Vector<WebMouseEvent>(), Vector<WebMouseEvent>());
 
-  ASSERT_EQ(callback->mouseEventCount(), 1);
-  ASSERT_EQ(callback->touchEventCount(), 1);
-  ASSERT_EQ(callback->penEventCount(), 1);
+  ASSERT_EQ(callback->numTypeMouseReceived(), 1);
+  ASSERT_EQ(callback->numTypeTouchReceived(), 1);
+  ASSERT_EQ(callback->numTypePenReceived(), 1);
+}
+
+TEST_F(PointerEventManagerTest, PointerCancelForNonExistentid) {
+  WebView().MainFrameViewWidget()->Resize(gfx::Size(400, 400));
+  SimRequest request("https://example.com/test.html", "text/html");
+  LoadURL("https://example.com/test.html");
+  request.Complete(
+      "<body style='padding: 0px; width: 400px; height: 400px;'>"
+      "<div draggable='true' style='width: 150px; height: 150px;'></div>"
+      "</body>");
+  auto* callback = MakeGarbageCollected<CheckPointerEventListenerCallback>();
+  GetDocument().body()->addEventListener(event_type_names::kPointercancel,
+                                         callback);
+
+  WebView().MainFrameWidget()->HandleInputEvent(WebCoalescedInputEvent(
+      CreateTestPointerEvent(WebInputEvent::Type::kPointerCancel,
+                             WebPointerProperties::PointerType::kTouch, 100),
+      {}, {}, ui::LatencyInfo()));
+
+  ASSERT_EQ(callback->numEventsReceived(), 0);
+
+  WebView().MainFrameWidget()->HandleInputEvent(WebCoalescedInputEvent(
+      CreateTestPointerEvent(WebInputEvent::Type::kPointerDown,
+                             WebPointerProperties::PointerType::kTouch, 100),
+      {}, {}, ui::LatencyInfo()));
+
+  ASSERT_EQ(callback->numEventsReceived(), 0);
+
+  WebView().MainFrameWidget()->HandleInputEvent(WebCoalescedInputEvent(
+      CreateTestPointerEvent(WebInputEvent::Type::kPointerCancel,
+                             WebPointerProperties::PointerType::kTouch, 100),
+      {}, {}, ui::LatencyInfo()));
+
+  ASSERT_EQ(callback->numEventsReceived(), 1);
+
+  WebView().MainFrameWidget()->HandleInputEvent(WebCoalescedInputEvent(
+      CreateTestPointerEvent(WebInputEvent::Type::kPointerCancel,
+                             WebPointerProperties::PointerType::kTouch, 200),
+      {}, {}, ui::LatencyInfo()));
+
+  ASSERT_EQ(callback->numEventsReceived(), 1);
 }
 
 TEST_F(PointerEventManagerTest, PointerEventCoordinates) {