Add ContentSuggestionsService

components/ntp_snippets/content_suggestion_category.h

Index: components/ntp_snippets/content_suggestion_category.h
diff --git a/components/ntp_snippets/content_suggestion_category.h b/components/ntp_snippets/content_suggestion_category.h
index 80268fbe1405ca4c8dc48ac516c5536c57997a3f..1b28c2b5bb83f7a053da1df038c07f303c84fa98 100644
--- a/components/ntp_snippets/content_suggestion_category.h
+++ b/components/ntp_snippets/content_suggestion_category.h
@@ -7,11 +7,9 @@
 
 namespace ntp_snippets {
 
-// The category of a content suggestion. Note that even though these categories
-// currently match the provider types, a provider type is not limited to provide
-// suggestions of a single (fixed) category only. The category is used to
-// determine where to display the suggestion.
-enum class ContentSuggestionCategory : int { ARTICLE };
+// The category of a content suggestion. The category is used to determine where
+// to display the suggestion.
+enum class ContentSuggestionCategory : int { ARTICLE, COUNT };
 
 }  // namespace ntp_snippets