[NTP Snippets] Metrics: switch over known categories

components/ntp_snippets/category.cc

Index: components/ntp_snippets/category.cc
diff --git a/components/ntp_snippets/category.cc b/components/ntp_snippets/category.cc
index c9dff3125dfc9c1ecdd92ce433f1c055f43efbe5..abc86ab9f2c71827710d8f2d477ec9206c170991 100644
--- a/components/ntp_snippets/category.cc
+++ b/components/ntp_snippets/category.cc
@@ -4,11 +4,15 @@
 
 #include "components/ntp_snippets/category.h"
 
+#include "base/logging.h"
+
 namespace ntp_snippets {
 
 Category::Category(int id) : id_(id) {}
 
 bool Category::IsKnownCategory(KnownCategories known_category) const {
+  DCHECK_NE(known_category, KnownCategories::LOCAL_CATEGORIES_COUNT);
+  DCHECK_NE(known_category, KnownCategories::REMOTE_CATEGORIES_OFFSET);
   return id_ == static_cast<int>(known_category);
 }