Release mouse pointer capture when it starts drag

third_party/WebKit/Source/core/events/PointerEventFactory.h

 // 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.
 
 #ifndef PointerEventFactory_h
 #define PointerEventFactory_h
 
 #include "core/CoreExport.h"
 #include "core/events/PointerEvent.h"
 #include "platform/wtf/Allocator.h"
 #include "platform/wtf/HashMap.h"
+#include "public/platform/WebPointerEvent.h"
 #include "public/platform/WebPointerProperties.h"
 
 namespace blink {
 
 // Helper class for tracking the pointer ids for each type of PointerEvents.
 // Using id re-mapping at this layer, this class makes sure that regardless of
 // the domain of the id (i.e. in touch or pen) the corresponding pointer event
 // will have a unique id amongst all pointer events as per pointer events'
 // specification. This class intended to behave the same as existing browsers as
 // much as possible for compatibility reasons. Particularly it behaves very
@@ skipping 12 matching lines @@
                        const Vector<WebMouseEvent>&,
                        LocalDOMWindow*);
 
   PointerEvent* Create(const WebTouchPoint&,
                        const Vector<std::pair<WebTouchPoint, TimeTicks>>&,
                        WebInputEvent::Modifiers,
                        TimeTicks event_platform_time_stamp,
                        LocalFrame*,
                        DOMWindow*);
 
+  PointerEvent* CreatePointerCancelEvent(const WebPointerEvent&);
+
   PointerEvent* CreatePointerCancelEvent(
       const int pointer_id,
       const WebPointerProperties::PointerType,
       TimeTicks platfrom_time_stamp);
 
   // For creating capture events (i.e got/lostpointercapture)
   PointerEvent* CreatePointerCaptureEvent(PointerEvent*, const AtomicString&);
 
   // For creating boundary events (i.e pointerout/leave/over/enter)
   PointerEvent* CreatePointerBoundaryEvent(PointerEvent*,
@@ skipping 74 matching lines @@
                       WebPointerProperties::PointerType::kLastEntry) +
                   1];
   int id_count_[static_cast<int>(
                     WebPointerProperties::PointerType::kLastEntry) +
                 1];
 };
 
 }  // namespace blink
 
 #endif  // PointerEventFactory_h