Fix grabbing capture when the mouse is pressed on Desktop Linux.

ui/events/devices/x11/device_data_manager_x11.cc

Index: ui/events/devices/x11/device_data_manager_x11.cc
diff --git a/ui/events/devices/x11/device_data_manager_x11.cc b/ui/events/devices/x11/device_data_manager_x11.cc
index 68fdb2cd30a6466e0dc8d8cc82fbd550ae4065ca..85c697aaa0d33376d8f60a81f768b4a11ad61acf 100644
--- a/ui/events/devices/x11/device_data_manager_x11.cc
+++ b/ui/events/devices/x11/device_data_manager_x11.cc
@@ -202,6 +202,7 @@ bool DeviceDataManagerX11::IsXInput2Available() const {
 void DeviceDataManagerX11::UpdateDeviceList(Display* display) {
   cmt_devices_.reset();
   touchpads_.reset();
+  master_pointers_.clear();
   for (int i = 0; i < kMaxDeviceNum; ++i) {
     valuator_count_[i] = 0;
     valuator_lookup_[i].clear();
@@ -233,6 +234,9 @@ void DeviceDataManagerX11::UpdateDeviceList(Display* display) {
   for (int i = 0; i < info_list.count; ++i) {
     XIDeviceInfo* info = info_list.devices + i;
 
+    if (info->use == XIMasterPointer)
+      master_pointers_.push_back(info->deviceid);
+
     // We currently handle only slave, non-keyboard devices
     if (info->use != XISlavePointer && info->use != XIFloatingSlave)
       continue;