ui: Cleanup class/struct forward declarations

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 410e163924b3a59147c9f1eb846d00eb6567b17a..5930a39df6823eb6a68afe8c4715eec797a16fd5 100644
--- a/components/previews/core/previews_experiments.h
+++ b/components/previews/core/previews_experiments.h
@@ -13,17 +13,28 @@ namespace params {
 
 // The maximum number of recent previews navigations the black list looks at to
 // determine if a host is blacklisted.
-size_t MaxStoredHistoryLengthForBlackList();
+size_t MaxStoredHistoryLengthForPerHostBlackList();
+
+// The maximum number of recent previews navigations the black list looks at to
+// determine if all previews navigations are disallowed.
+size_t MaxStoredHistoryLengthForHostIndifferentBlackList();
 
 // 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 for a given host that
+// would trigger that host to be blacklisted.
+int PerHostBlackListOptOutThreshold();
+
 // The number of recent navigations that were opted out of that would trigger
-// the host to be blacklisted.
-int BlackListOptOutThreshold();
+// all previews navigations to be disallowed.
+int HostIndifferentBlackListOptOutThreshold();
 
 // The amount of time a host remains blacklisted due to opt outs.
-base::TimeDelta BlackListDuration();
+base::TimeDelta PerHostBlackListDuration();
+
+// The amount of time all previews navigations are disallowed due to opt outs.
+base::TimeDelta HostIndifferentBlackListPerHostDuration();
 
 // The amount of time after any opt out that no previews should be shown.
 base::TimeDelta SingleOptOutDuration();