Release mouse pointer capture when it starts drag

third_party/WebKit/Source/core/events/PointerEventFactory.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/events/PointerEventFactory.h"
 
 #include "core/frame/LocalFrameView.h"
 #include "platform/geometry/FloatSize.h"
 
 namespace blink {
@@ skipping 351 matching lines @@
       coalesced_pointer_events.push_back(event);
     }
     pointer_event_init.setCoalescedEvents(coalesced_pointer_events);
   }
 
   return PointerEvent::Create(type, pointer_event_init,
                               event_platform_time_stamp);
 }
 
 PointerEvent* PointerEventFactory::CreatePointerCancelEvent(
+    const WebPointerEvent& event) {
+  DCHECK_EQ(event.GetType(), WebInputEvent::Type::kPointerCancel);
+  int pointer_id = GetPointerEventId(event);
+
+  return CreatePointerCancelEvent(
+      pointer_id, event.pointer_type,
+      TimeTicks::FromSeconds(event.TimeStampSeconds()));
+}
+
+PointerEvent* PointerEventFactory::CreatePointerCancelEvent(
     const int pointer_id,
     const WebPointerProperties::PointerType pointer_type,
     TimeTicks platfrom_time_stamp) {
   DCHECK(pointer_id_mapping_.Contains(pointer_id));
   pointer_id_mapping_.Set(
       pointer_id,
       PointerAttributes(pointer_id_mapping_.at(pointer_id).incoming_id, false));
 
   PointerEventInit pointer_event_init;
 
@@ skipping 178 matching lines @@
     const WebPointerProperties& properties) const {
   if (properties.pointer_type == WebPointerProperties::PointerType::kMouse)
     return PointerEventFactory::kMouseId;
   IncomingId id(properties.pointer_type, properties.id);
   if (pointer_incoming_id_mapping_.Contains(id))
     return pointer_incoming_id_mapping_.at(id);
   return PointerEventFactory::kInvalidId;
 }
 
 }  // namespace blink