Fix touch screen on Linux with or without flag --touch-devices

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 112 matching lines @@
 
     if (devinfo.use == XIFloatingSlave || devinfo.use == XISlavePointer) {
       for (int k = 0; k < devinfo.num_classes; ++k) {
         XIAnyClassInfo* xiclassinfo = devinfo.classes[k];
         if (xiclassinfo->type == XITouchClass) {
           XITouchClassInfo* tci =
               reinterpret_cast<XITouchClassInfo*>(xiclassinfo);
           // Only care direct touch device (such as touch screen) right now
           if (tci->mode == XIDirectTouch)
             CacheTouchscreenIds(devinfo.deviceid);
+            if (devinfo.use == XISlavePointer) {
+              device_master_id_list_[devinfo.deviceid] = devinfo.attachment;
+              // If the slave device is direct touch device, we also set its
+              // master device to be touch device.
+              touch_device_lookup_[devinfo.attachment] = true;
+              touch_device_list_[devinfo.attachment] = true;
+            }
         }
       }
     }
   }
 }
 
 bool TouchFactory::ShouldProcessXI2Event(XEvent* xev) {
   DCHECK_EQ(GenericEvent, xev->type);
   XIEvent* event = static_cast<XIEvent*>(xev->xcookie.data);
   XIDeviceEvent* xiev = reinterpret_cast<XIDeviceEvent*>(event);
@@ skipping 69 matching lines @@
   evmask.deviceid = XIAllDevices;
   evmask.mask_len = sizeof(mask);
   evmask.mask = mask;
   XISelectEvents(display, window, &evmask, 1);
   XFlush(display);
 }
 
 void TouchFactory::SetTouchDeviceList(const std::vector<int>& devices) {
   touch_device_lookup_.reset();
   touch_device_list_.clear();
-  for (std::vector<int>::const_iterator iter = devices.begin();
-       iter != devices.end(); ++iter) {
-    DCHECK(IsValidDevice(*iter));
-    touch_device_lookup_[*iter] = true;
-    touch_device_list_[*iter] = false;
+  for (int deviceid : devices) {
+    DCHECK(IsValidDevice(deviceid));
+    touch_device_lookup_[deviceid] = true;
+    touch_device_list_[deviceid] = false;
+    if (device_master_id_list_.find(deviceid) != device_master_id_list_.end()) {
+      // When we set the device through the "--touch-devices" flag to slave
+      // touch device, we also set its master device to be touch device.
+      touch_device_lookup_[device_master_id_list_[deviceid]] = true;
+      touch_device_list_[device_master_id_list_[deviceid]] = false;
+    }
   }
 }
 
 bool TouchFactory::IsValidDevice(int deviceid) const {
   return (deviceid >= 0) &&
          (static_cast<size_t>(deviceid) < touch_device_lookup_.size());
 }
 
 bool TouchFactory::IsTouchDevice(int deviceid) const {
   return IsValidDevice(deviceid) ? touch_device_lookup_[deviceid] : false;
@@ skipping 64 matching lines @@
       std::find_if(touchscreens.begin(), touchscreens.end(),
                    [device_id](const TouchscreenDevice& touchscreen) {
                      return touchscreen.id == device_id;
                    });
   // Internal displays will have a vid and pid of 0. Ignore them.
   if (it != touchscreens.end() && it->vendor_id && it->product_id)
     touchscreen_ids_.insert(std::make_pair(it->vendor_id, it->product_id));
 }
 
 }  // namespace ui