Generalize Previews Type code

components/previews/core/previews_opt_out_store_sql.h

Index: components/previews/core/previews_opt_out_store_sql.h
diff --git a/components/previews/core/previews_opt_out_store_sql.h b/components/previews/core/previews_opt_out_store_sql.h
index 33cdef088b22424215a54a19b24df405513d9e59..801b85074471063f309ce6d88dc9254a862af51b 100644
--- a/components/previews/core/previews_opt_out_store_sql.h
+++ b/components/previews/core/previews_opt_out_store_sql.h
@@ -8,20 +8,21 @@
 #include <stdint.h>
 
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/files/file_path.h"
 #include "base/macros.h"
 #include "base/threading/thread_checker.h"
 #include "base/time/time.h"
+#include "components/previews/core/previews_experiments.h"
 #include "components/previews/core/previews_opt_out_store.h"
 
 namespace base {
 class SequencedTaskRunner;
 class SingleThreadTaskRunner;
 }
 
 namespace sql {
 class Connection;
 }