MetaMonitor: Add _is_laptop_panel() helper

Add a helper to determine whether the monitor is the laptop panel or
not. To be used by the configuration system.

https://bugzilla.gnome.org/show_bug.cgi?id=777732

src/backends/meta-monitor.c

@@ -164,6 +164,24 @@ meta_monitor_is_primary (MetaMonitor *monitor)
   return output->is_primary;
 }
 
+gboolean
+meta_monitor_is_laptop_panel (MetaMonitor *monitor)
+{
+  MetaOutput *output;
+
+  output = meta_monitor_get_main_output (monitor);
+
+  switch (output->connector_type)
+    {
+    case META_CONNECTOR_TYPE_eDP:
+    case META_CONNECTOR_TYPE_LVDS:
+    case META_CONNECTOR_TYPE_DSI:
+      return TRUE;
+    default:
+      return FALSE;
+    }
+}
+
 void
 meta_monitor_get_dimensions (MetaMonitor   *monitor,
                              int           *width,

src/backends/meta-monitor.h

@@ -92,6 +92,8 @@ MetaOutput * meta_monitor_get_main_output (MetaMonitor *monitor);
 
 gboolean meta_monitor_is_primary (MetaMonitor *monitor);
 
+gboolean meta_monitor_is_laptop_panel (MetaMonitor *monitor);
+
 GList * meta_monitor_get_outputs (MetaMonitor *monitor);
 
 void meta_monitor_get_dimensions (MetaMonitor   *monitor,