Bookkeep the pointer event listeners added to page

third_party/WebKit/Source/core/input/PointerEventManager.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/input/PointerEventManager.h"
 
 #include "core/dom/ElementTraversal.h"
 #include "core/dom/UserGestureIndicator.h"
 #include "core/dom/shadow/FlatTreeTraversal.h"
 #include "core/events/MouseEvent.h"
+#include "core/frame/EventHandlerRegistry.h"
 #include "core/frame/LocalFrameView.h"
 #include "core/frame/UseCounter.h"
 #include "core/html/HTMLCanvasElement.h"
 #include "core/input/EventHandler.h"
 #include "core/input/EventHandlingUtil.h"
 #include "core/input/MouseEventManager.h"
 #include "core/input/TouchActionUtil.h"
 #include "core/layout/HitTestCanvasResult.h"
 #include "core/page/ChromeClient.h"
 #include "core/page/Page.h"
 #include "platform/wtf/AutoReset.h"
 #include "public/platform/WebTouchEvent.h"
 
 namespace blink {
 
 namespace {
 
 size_t ToPointerTypeIndex(WebPointerProperties::PointerType t) {
   return static_cast<size_t>(t);
 }
+bool HasPointerEventListener(const EventHandlerRegistry& registry) {
+  return registry.HasEventHandlers(EventHandlerRegistry::kPointerEvent);
+}
 
 Vector<std::pair<WebTouchPoint, TimeTicks>> GetCoalescedPoints(
     const Vector<WebTouchEvent>& coalesced_events,
     int id) {
   Vector<std::pair<WebTouchPoint, TimeTicks>> related_points;
   for (const auto& touch_event : coalesced_events) {
     for (unsigned i = 0; i < touch_event.touches_length; ++i) {
       if (touch_event.touches[i].id == id &&
           touch_event.touches[i].state != WebTouchPoint::kStateStationary) {
         related_points.push_back(std::pair<WebTouchPoint, TimeTicks>(
@@ skipping 111 matching lines @@
     EventTarget* target_under_pointer =
         node_under_pointer_.at(pointer_id).target;
     if (target_under_pointer == target) {
       node_under_pointer_.Set(
           pointer_id,
           EventTargetAttributes(target_under_pointer,
                                 event_type == EventTypeNames::pointerover));
     }
   }
 
-  if (!RuntimeEnabledFeatures::PointerEventEnabled())
+  if (!frame_ || !frame_->GetPage() ||
+      !HasPointerEventListener(frame_->GetPage()->GetEventHandlerRegistry()) ||
+      !RuntimeEnabledFeatures::PointerEventEnabled())
     return WebInputEventResult::kNotHandled;
+
   if (!check_for_listener || target->HasEventListeners(event_type)) {
     UseCounter::Count(frame_, UseCounter::kPointerEventDispatch);
     if (event_type == EventTypeNames::pointerdown)
       UseCounter::Count(frame_, UseCounter::kPointerEventDispatchPointerDown);
 
     DCHECK(!dispatching_pointer_id_);
     AutoReset<int> dispatch_holder(&dispatching_pointer_id_, pointer_id);
     DispatchEventResult dispatch_result = target->DispatchEvent(pointer_event);
     return EventHandlingUtil::ToWebInputEventResult(dispatch_result);
   }
@@ skipping 571 matching lines @@
     if (first_id > unique_touch_event_id)
       return false;
     touch_ids_for_canceled_pointerdowns_.TakeFirst();
     if (first_id == unique_touch_event_id)
       return true;
   }
   return false;
 }
 
 }  // namespace blink