Topo2: Refactored Maps and Sprites to be managed by a BackgroundService

Change-Id: I75965fc76734436ce0c68e06dd75663baa924287
diff --git a/web/gui/src/main/webapp/app/view/topo2/topo2.html b/web/gui/src/main/webapp/app/view/topo2/topo2.html
index b36a036..c83c4ce 100644
--- a/web/gui/src/main/webapp/app/view/topo2/topo2.html
+++ b/web/gui/src/main/webapp/app/view/topo2/topo2.html
@@ -32,7 +32,7 @@
 
     <!-- Below here is good; Above here is temporary, for debugging -->
 
-    <svg viewBox="0 0 1000 1000"
+    <svg viewBox="0 0 1000 1000" id="topo2"
         resize offset-height="56" offset-width="12"
         notifier="notifyResize()">
     </svg>