Move all geofencing code into its own module separate from geolocation.

Source/modules/geofencing/Geofencing.idl

Index: Source/modules/geofencing/Geofencing.idl
diff --git a/Source/modules/geolocation/GeofencingRegion.idl b/Source/modules/geofencing/Geofencing.idl
similarity index 51%
copy from Source/modules/geolocation/GeofencingRegion.idl
copy to Source/modules/geofencing/Geofencing.idl
index 4e22058d98b22fb2f0a7d196263ea4b9a458feab..7b36e70cfbbcbcaf250a778a7454e0b5babfe32d 100644
--- a/Source/modules/geolocation/GeofencingRegion.idl
+++ b/Source/modules/geofencing/Geofencing.idl
@@ -3,9 +3,11 @@
 // found in the LICENSE file.
 
 [
-    RuntimeEnabled=Geofencing,
     NoInterfaceObject,
+    RuntimeEnabled=Geofencing,
     GarbageCollected,
-] interface GeofencingRegion {
-    readonly attribute DOMString id;
+] interface Geofencing {
+    [CallWith=ScriptState] Promise registerRegion(GeofencingRegion region);
+    [CallWith=ScriptState] Promise unregisterRegion(DOMString regionId);
+    [CallWith=ScriptState] Promise getRegisteredRegions();
 };