Add the Polymer object observe library and add a test that it works.

perf/server/bower.json

Index: perf/server/bower.json
diff --git a/perf/server/bower.json b/perf/server/bower.json
index eff7fc41eb52b3980cecb349abdfe170b95ba29e..e08a1332532c41f417deae7a116f79c0a287e74d 100644
--- a/perf/server/bower.json
+++ b/perf/server/bower.json
@@ -17,6 +17,7 @@
     "flot": "~0.8.3",
     "pointerevents-polyfill": "~0.2.0",
     "CustomElements": "~0.2.4",
-    "HTMLImports": "~0.2.3"
+    "HTMLImports": "~0.2.3",
+    "observe-js": "~0.3.3"
   }
 }