Render batch bounds as stroke rects

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1745063002

Review URL: https://codereview.chromium.org/1745063002
diff --git a/tools/skiaserve/skiaserve.cpp b/tools/skiaserve/skiaserve.cpp
index b593e72..195544e 100644
--- a/tools/skiaserve/skiaserve.cpp
+++ b/tools/skiaserve/skiaserve.cpp
@@ -39,6 +39,7 @@
         fHandlers.push_back(new DataHandler);
         fHandlers.push_back(new BreakHandler);
         fHandlers.push_back(new BatchesHandler);
+        fHandlers.push_back(new BatchBoundsHandler);
     }
 
     ~UrlManager() {