win32u: Store output id in monitors cache.

dlls/win32u/sysparams.c

@@ -226,6 +226,7 @@ struct monitor
     HANDLE handle;
     unsigned int id;
     unsigned int flags;
+    unsigned int output_id;
     RECT rc_monitor;
     RECT rc_work;
     BOOL is_clone;
@@ -714,6 +715,17 @@ static BOOL read_monitor_settings( struct adapter *adapter, DWORD index, struct
     }
     monitor->dev.state_flags = *(const DWORD *)value->Data;
 
+    /* Output ID */
+    size = query_reg_subkey_value( hkey, devpropkey_monitor_output_idW,
+                                   sizeof(devpropkey_monitor_output_idW),
+                                   value, sizeof(buffer) );
+    if (size != sizeof(monitor->output_id))
+    {
+        NtClose( hkey );
+        return FALSE;
+    }
+    monitor->output_id = *(const unsigned int *)value->Data;
+
     /* rc_monitor, WINE_DEVPROPKEY_MONITOR_RCMONITOR */
     size = query_reg_subkey_value( hkey, wine_devpropkey_monitor_rcmonitorW,
                                    sizeof(wine_devpropkey_monitor_rcmonitorW),