Make ModelLoader to release URLFeatcher once fetching is done.

chrome/browser/safe_browsing/client_side_model_loader.cc

Index: chrome/browser/safe_browsing/client_side_model_loader.cc
diff --git a/chrome/browser/safe_browsing/client_side_model_loader.cc b/chrome/browser/safe_browsing/client_side_model_loader.cc
index 5519b4108b0cdf907a65ff6815bc52de9dc30a40..30e181a5c8fd0ba51def346b93e672925ba1e092 100644
--- a/chrome/browser/safe_browsing/client_side_model_loader.cc
+++ b/chrome/browser/safe_browsing/client_side_model_loader.cc
@@ -189,6 +189,9 @@ void ModelLoader::EndFetch(ClientModelStatus status, base::TimeDelta max_age) {
     delay_ms = max_age.InMilliseconds();
   }
 
+  // Reset |fetcher_| as it will be re-created on next fetch.
+  fetcher_.reset();
+
   // Schedule the next model reload.
   ScheduleFetch(delay_ms);
 }