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

ui/events/devices/x11/touch_factory_x11.cc

Index: ui/events/devices/x11/touch_factory_x11.cc
diff --git a/ui/events/devices/x11/touch_factory_x11.cc b/ui/events/devices/x11/touch_factory_x11.cc
index 1dce5048d6bff599e5ff41b83035b0885c2a4949..d04231bb141d43c96e1ef1b8c572b58d84e12051 100644
--- a/ui/events/devices/x11/touch_factory_x11.cc
+++ b/ui/events/devices/x11/touch_factory_x11.cc
@@ -201,6 +201,8 @@ void TouchFactory::SetupXI2ForXWindow(Window window) {
   XISetMask(mask, XI_ButtonRelease);
   XISetMask(mask, XI_Motion);
 #if defined(OS_CHROMEOS)
+  // XGrabKey() must be replaced with XI2 keyboard grab if XI2 key events are
+  // enabled on desktop Linux.
   if (base::SysInfo::IsRunningOnChromeOS()) {
     XISetMask(mask, XI_KeyPress);
     XISetMask(mask, XI_KeyRelease);