Plumb maxTouchPoints for AuraX11

ui/events/x/touch_factory_x11.cc

Index: ui/events/x/touch_factory_x11.cc
diff --git a/ui/events/x/touch_factory_x11.cc b/ui/events/x/touch_factory_x11.cc
index 84066e3cb0b3391e690b7f21a47c82baddabfd3e..da9d95ab8ad2930fbf7870f6706987ac7a775dda 100644
--- a/ui/events/x/touch_factory_x11.cc
+++ b/ui/events/x/touch_factory_x11.cc
@@ -29,6 +29,7 @@ TouchFactory::TouchFactory()
       touch_device_available_(false),
       touch_events_disabled_(false),
       touch_device_list_(),
+      max_touch_points_(-1),
       id_generator_(0) {
   if (!DeviceDataManager::GetInstance()->IsXInput2Available())
     return;
@@ -80,6 +81,7 @@ void TouchFactory::UpdateDeviceList(Display* display) {
   touch_device_available_ = false;
   touch_device_lookup_.reset();
   touch_device_list_.clear();
+  max_touch_points_ = -1;
 
 #if !defined(USE_XI2_MT)
   // NOTE: The new API for retrieving the list of devices (XIQueryDevice) does
@@ -132,6 +134,8 @@ void TouchFactory::UpdateDeviceList(Display* display) {
             touch_device_lookup_[devinfo->deviceid] = true;
             touch_device_list_[devinfo->deviceid] = true;
             touch_device_available_ = true;
+            if (tci->num_touches > 0 && tci->num_touches > max_touch_points_)
+              max_touch_points_ = tci->num_touches;
           }
         }
       }
@@ -237,6 +241,10 @@ bool TouchFactory::IsTouchDevicePresent() {
   return !touch_events_disabled_ && touch_device_available_;
 }
 
+int TouchFactory::GetMaxTouchPoints() const {
+  return max_touch_points_;
+}
+
 void TouchFactory::SetTouchDeviceForTest(
     const std::vector<unsigned int>& devices) {
   touch_device_lookup_.reset();