Adding a short blacklist period after every previews opt out

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..410e163924b3a59147c9f1eb846d00eb6567b17a 100644
--- a/components/previews/core/previews_experiments.h
+++ b/components/previews/core/previews_experiments.h
@@ -18,20 +18,23 @@ size_t MaxStoredHistoryLengthForBlackList();
 // The maximum number of hosts allowed in the in memory black list.
 size_t MaxInMemoryHostsInBlackList();
 
 // The number of recent navigations that were opted out of that would trigger
 // the host to be blacklisted.
 int BlackListOptOutThreshold();
 
 // The amount of time a host remains blacklisted due to opt outs.
 base::TimeDelta BlackListDuration();
 
+// The amount of time after any opt out that no previews should be shown.
+base::TimeDelta SingleOptOutDuration();
+
 }  // namespace params
 
 enum class PreviewsType {
   NONE = 0,
   OFFLINE = 1,
   LAST = 2,
 };
 
 // Returns true if any client-side previews experiment is active.
 bool IsIncludedInClientSidePreviewsExperimentsFieldTrial();