Check that XOpenDevice() returns valid device_id.

ui/events/platform/x11/x11_hotplug_event_handler.cc

 // Copyright 2014 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/platform/x11/x11_hotplug_event_handler.h"
 
 #include <stdint.h>
 #include <X11/extensions/XInput.h>
 #include <X11/extensions/XInput2.h>
 #include <X11/Xatom.h>
@@ skipping 197 matching lines @@
   // e.g.   Device Node (250): "/dev/input/event8"
   Atom device_node = XInternAtom(dpy, "Device Node", False);
   if (device_node == None)
     return base::FilePath();
 
   Atom actual_type;
   int actual_format;
   unsigned long nitems, bytes_after;
   unsigned char* data;
   XDevice* dev = XOpenDevice(dpy, device.deviceid);
-  if (!dev)
+
+  // Sometimes XOpenDevice() doesn't return null but the contents aren't valid.
+  // Calling XGetDeviceProperty() when dev->device_id is invalid triggers a
+  // BadDevice error. Return early to avoid a crash. http://crbug.com/659261
+  if (!dev || dev->device_id != base::checked_cast<XID>(device.deviceid))
     return base::FilePath();
 
   if (XGetDeviceProperty(dpy,
                          dev,
                          device_node,
                          0,
                          1000,
                          False,
                          AnyPropertyType,
                          &actual_type,
@@ skipping 264 matching lines @@
   // worker thread. Once the device information is extracted the parsed devices
   // will be returned via the callbacks.
   base::WorkerPool::PostTask(
       FROM_HERE,
       base::Bind(&HandleHotplugEventInWorker, device_infos, display_state,
                  base::ThreadTaskRunnerHandle::Get(), callbacks),
       true /* task_is_slow */);
 }
 
 }  // namespace ui