Adding unit tests for PreviewsOptOutStoreSQL

components/previews/core/previews_experiments.h

Index: components/previews/core/previews_experiments.h
diff --git a/components/previews/core/previews_experiments.h b/components/previews/core/previews_experiments.h
index 520b45fb65b6cd678159521bb8364288215eab80..c27afe9d42ce4eacfd79a5e21140eb8a44fbe1cd 100644
--- a/components/previews/core/previews_experiments.h
+++ b/components/previews/core/previews_experiments.h
@@ -26,20 +26,28 @@ int BlackListOptOutThreshold();
 base::TimeDelta BlackListDuration();
 
 }  // namespace params
 
 enum class PreviewsType {
   NONE = 0,
   OFFLINE = 1,
   LAST = 2,
 };
 
+// Returns the maximum number of table rows allowed per host for the previews
+// opt out store.
+int MaxRowsPerHostInOptOutDB();
+
+// Returns the maximum number of table rows allowed for the previews opt out
+// store.
+int MaxRowsInOptOutDB();
+
 // Returns true if any client-side previews experiment is active.
 bool IsIncludedInClientSidePreviewsExperimentsFieldTrial();
 
 // Returns true if the field trial that should enable previews for |type| for
 // prohibitvely slow networks is active.
 bool IsPreviewsTypeEnabled(PreviewsType type);
 
 // Sets the appropriate state for field trial and variations to imitate the
 // offline pages field trial.
 bool EnableOfflinePreviewsForTesting();