Reporting: Cap number of clients in cache.

net/reporting/reporting_policy.h

Index: net/reporting/reporting_policy.h
diff --git a/net/reporting/reporting_policy.h b/net/reporting/reporting_policy.h
index 98e1a4a5e4ec0481942559b6b668f3875f1aafc0..772bff51f030e475552f90b0c7dcff43b28164bc 100644
--- a/net/reporting/reporting_policy.h
+++ b/net/reporting/reporting_policy.h
@@ -21,6 +21,9 @@ struct NET_EXPORT ReportingPolicy {
   // Maximum number of reports to queue before evicting the oldest.
   size_t max_report_count;
 
+  // Maximum number of clients to remember before evicting least-recently-used.
+  size_t max_client_count;
+
   // Minimum interval at which to attempt delivery of queued reports.
   base::TimeDelta delivery_interval;