A mouse event created from the same native event will be marked as repeated.

ui/events/event.cc

 // Copyright (c) 2012 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 "ui/events/event.h"
 
 #if defined(USE_X11)
 #include <X11/extensions/XInput2.h>
 #include <X11/keysym.h>
 #include <X11/Xlib.h>
@@ skipping 339 matching lines @@
 
   if (event1.type() != ET_MOUSE_PRESSED ||
       event2.type() != ET_MOUSE_PRESSED)
     return false;
 
   // Compare flags, but ignore EF_IS_DOUBLE_CLICK to allow triple clicks.
   if ((event1.flags() & ~EF_IS_DOUBLE_CLICK) !=
       (event2.flags() & ~EF_IS_DOUBLE_CLICK))
     return false;
 
+  // The new event has been created from the same native event.
+  if (event1.time_stamp() == event2.time_stamp())
+    return false;
+
   base::TimeDelta time_difference = event2.time_stamp() - event1.time_stamp();
 
   if (time_difference.InMilliseconds() > kDoubleClickTimeMS)
     return false;
 
   if (std::abs(event2.x() - event1.x()) > kDoubleClickWidth / 2)
     return false;
 
   if (std::abs(event2.y() - event1.y()) > kDoubleClickHeight / 2)
     return false;
@@ skipping 614 matching lines @@
                    gfx::PointF(x, y),
                    time_stamp,
                    flags | EF_FROM_TOUCH),
       details_(details) {
 }
 
 GestureEvent::~GestureEvent() {
 }
 
 }  // namespace ui