Set the target lazily for the coalesced events

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

 /*
  * Copyright (C) 2001 Peter Kelly (pmk@post.com)
  * Copyright (C) 2001 Tobias Anton (anton@stud.fbi.fh-darmstadt.de)
  * Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2008 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 202 matching lines @@
   MouseEvent(const AtomicString& type,
              const MouseEventInit&,
              TimeTicks platform_time_stamp);
   MouseEvent(const AtomicString& type, const MouseEventInit& init)
       : MouseEvent(type, init, TimeTicks::Now()) {}
 
   MouseEvent();
 
   short RawButton() const { return button_; }
 
+  void ReceivedTarget() override;
+
  private:
   friend class MouseEventDispatchMediator;
   void InitMouseEventInternal(const AtomicString& type,
                               bool can_bubble,
                               bool cancelable,
                               AbstractView*,
                               int detail,
                               int screen_x,
                               int screen_y,
                               int client_x,
                               int client_y,
                               WebInputEvent::Modifiers,
                               short button,
                               EventTarget* related_target,
                               InputDeviceCapabilities* source_capabilities,
                               unsigned short buttons = 0);
 
   void InitCoordinates(const double client_x, const double client_y);
   void InitCoordinatesFromRootFrame(int window_x, int window_y);
-  void ReceivedTarget() final;
 
   void ComputePageLocation();
   void ComputeRelativePosition();
 
   DoublePoint screen_location_;
   DoublePoint client_location_;
   DoublePoint movement_delta_;
 
   DoublePoint page_location_;
   DoublePoint layer_location_;
@@ skipping 18 matching lines @@
   MouseEvent& Event() const;
 
   DispatchEventResult DispatchEvent(EventDispatcher&) const override;
 };
 
 DEFINE_EVENT_TYPE_CASTS(MouseEvent);
 
 }  // namespace blink
 
 #endif  // MouseEvent_h