Connecting UserClassifier to NtpSnippetsFetcher

components/ntp_snippets/user_classifier.cc

Index: components/ntp_snippets/user_classifier.cc
diff --git a/components/ntp_snippets/user_classifier.cc b/components/ntp_snippets/user_classifier.cc
index a9122343a1ee3e2977c2416e02121463455b04e1..d25cb2256a1d36bc822d2529f99bf62738eee321 100644
--- a/components/ntp_snippets/user_classifier.cc
+++ b/components/ntp_snippets/user_classifier.cc
@@ -267,6 +267,10 @@ double UserClassifier::GetEstimatedAvgTime(Metric metric) const {
 }
 
 UserClassifier::UserClass UserClassifier::GetUserClass() const {
+  // The pref_service_ can be null in tests.
+  if (!pref_service_)
+    return UserClass::ACTIVE_NTP_USER;
+
   if (GetEstimatedAvgTime(Metric::NTP_OPENED) >=
       rare_user_opens_ntp_at_most_once_per_hours_) {
     return UserClass::RARE_NTP_USER;