Merge changes I779b0fb2,Icb8c8408,I96f9a8e8

* changes:
  DefaultRefFilter: Add debug logs for tracing
  DefaultRefFilter#visibleEdit: Improve readability
  Ensure that groups are always logged when request is traced
diff --git a/lib/js/npm.bzl b/lib/js/npm.bzl
index 8a9e1ee..5a6a8c0 100644
--- a/lib/js/npm.bzl
+++ b/lib/js/npm.bzl
@@ -1,11 +1,11 @@
 NPM_VERSIONS = {
     "bower": "1.8.8",
     "crisper": "2.0.2",
-    "polymer-bundler": "4.0.2",
+    "polymer-bundler": "4.0.9",
 }
 
 NPM_SHA1S = {
     "bower": "82544be34a33aeae7efb8bdf9905247b2cffa985",
     "crisper": "7183c58cea33632fb036c91cefd1b43e390d22a2",
-    "polymer-bundler": "6b296b6099ab5a0e93ca914cbe93e753f2395910",
+    "polymer-bundler": "c80c9815690d76656d1fa6a231481850b4fa3874",
 }