Add a PrefetchList to Prerender Local Predictor, to emulate how effective

chrome/browser/prerender/prerender_field_trial.h

Index: chrome/browser/prerender/prerender_field_trial.h
diff --git a/chrome/browser/prerender/prerender_field_trial.h b/chrome/browser/prerender/prerender_field_trial.h
index ef7c6e316adf93d8db0fc2f275bb0c8be4f89514..e4a1a285367554f936b166ee1229843f5786d3e2 100644
--- a/chrome/browser/prerender/prerender_field_trial.h
+++ b/chrome/browser/prerender/prerender_field_trial.h
@@ -71,6 +71,9 @@ int GetPrerenderServiceBehaviorID();
 // Returns the fetch timeout to be used for the prerender service, in ms.
 int GetPrerenderServiceFetchTimeoutMs();
 
+// Returns the timeout for entries in the prefetch list, in seconds.
+int GetPrerenderPrefetchListTimeoutSeconds();
+
 // Returns the TTL to be used for the local predictor.
 int GetLocalPredictorTTLSeconds();