Prevent TouchEvent Crash on X

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 564 matching lines @@
       radius_x_(radius_x),
       radius_y_(radius_y),
       rotation_angle_(angle),
       force_(force),
       may_cause_scrolling_(false),
       should_remove_native_touch_id_mapping_(false) {
   latency()->AddLatencyNumber(INPUT_EVENT_LATENCY_UI_COMPONENT, 0, 0);
   FixRotationAngle();
 }
 
+TouchEvent::TouchEvent(const TouchEvent& copy)
+    : LocatedEvent(copy),
+      touch_id_(copy.touch_id_),
+      unique_event_id_(copy.unique_event_id_),
+      radius_x_(copy.radius_x_),
+      radius_y_(copy.radius_y_),
+      rotation_angle_(copy.rotation_angle_),
+      force_(copy.force_),
+      may_cause_scrolling_(copy.may_cause_scrolling_),
+      should_remove_native_touch_id_mapping_(false) {
+  // Copied events should not remove touch id mapping, as this either causes the
+  // mapping to be lost before the initial event has finished dispatching, or
+  // the copy to attempt to remove the mapping from a null |native_event_|.
+}
+
 TouchEvent::~TouchEvent() {
   // In ctor TouchEvent(native_event) we call GetTouchId() which in X11
   // platform setups the tracking_id to slot mapping. So in dtor here,
   // if this touch event is a release event, we clear the mapping accordingly.
   if (should_remove_native_touch_id_mapping_) {
     DCHECK(type() == ET_TOUCH_RELEASED || type() == ET_TOUCH_CANCELLED);
     if (type() == ET_TOUCH_RELEASED || type() == ET_TOUCH_CANCELLED)
       ClearTouchIdIfReleased(native_event());
   }
 }
@@ skipping 386 matching lines @@
                    gfx::PointF(x, y),
                    time_stamp,
                    flags | EF_FROM_TOUCH),
       details_(details) {
 }
 
 GestureEvent::~GestureEvent() {
 }
 
 }  // namespace ui