Make the Mouse integration work in Virtualbox

ui/events/devices/x11/touch_factory_x11.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/devices/x11/touch_factory_x11.h"
 
 #include <X11/Xatom.h>
 #include <X11/cursorfont.h>
 #include <X11/extensions/XInput.h>
 #include <X11/extensions/XInput2.h>
@@ skipping 65 matching lines @@
     ui::TouchFactory::GetInstance()->SetTouchDeviceList(device_ids);
   }
 }
 
 void TouchFactory::UpdateDeviceList(Display* display) {
   // Detect touch devices.
   touch_device_lookup_.reset();
   touch_device_list_.clear();
   touchscreen_ids_.clear();
 
-  // NOTE: The new API for retrieving the list of devices (XIQueryDevice) does
-  // not provide enough information to detect a touch device. As a result, the
-  // old version of query function (XListInputDevices) is used instead.
-  // If XInput2 is not supported, this will return null (with count of -1) so
-  // we assume there cannot be any touch devices.
+  // NOTE: If XInput2 is not supported, this will return null (with count of
+  // -1) so we assume there cannot be any touch devices.
   // With XI2.1 or older, we allow only single touch devices.

[sadrul, 2015/03/30 21:19:00]

Not sure what you mean by 'this will return null'. Do you mean this function, or
the call to GetXIDeviceList(), or the call to GetXDeviceList()?

I think you can just remove this entire comment.

[lanwei, 2015/03/30 21:36:28]

I mean the two lists, touch_device_lookup_, touch_device_list_, because they are
not setup. Never mind, the comments seem unnecessary, I removed it.

Done.

-  const XDeviceList& dev_list =
-      DeviceListCacheX11::GetInstance()->GetXDeviceList(display);
-  Atom xi_touchscreen = XInternAtom(display, XI_TOUCHSCREEN, false);
-  for (int i = 0; i < dev_list.count; i++) {
-    if (dev_list[i].type == xi_touchscreen) {
-      touch_device_lookup_[dev_list[i].id] = true;
-      touch_device_list_[dev_list[i].id] = false;
-    }
-  }
-
   if (!DeviceDataManagerX11::GetInstance()->IsXInput2Available())
     return;
 
   // Instead of asking X for the list of devices all the time, let's maintain a
   // list of pointer devices we care about.
   // It should not be necessary to select for slave devices. XInput2 provides
   // enough information to the event callback to decide which slave device
   // triggered the event, thus decide whether the 'pointer event' is a
   // 'mouse event' or a 'touch event'.
   // However, on some desktops, some events from a master pointer are
@@ skipping 227 matching lines @@
       if (ptr[0] || ptr[1])
         touchscreen_ids_.insert(std::make_pair(ptr[0], ptr[1]));
     }
     XFree(prop_return);
   }
 
   XCloseDevice(display, device);
 }
 
 }  // namespace ui