Add UMA metrics for the time it takes to read store from disk and apply update

components/safe_browsing_db/v4_store.h

Index: components/safe_browsing_db/v4_store.h
diff --git a/components/safe_browsing_db/v4_store.h b/components/safe_browsing_db/v4_store.h
index d4559780cae063ccfeae55d8a14f29f33bff8082..f0172808c8f92d8b0df83b25a174801190c2ac8a 100644
--- a/components/safe_browsing_db/v4_store.h
+++ b/components/safe_browsing_db/v4_store.h
@@ -290,12 +290,6 @@ class V4Store {
   static void ReserveSpaceInPrefixMap(const HashPrefixMap& other_prefixes_map,
                                       HashPrefixMap* prefix_map_to_update);
 
-  // Updates the |additions_map| with the additions received in the partial
-  // update from the server.
-  static ApplyUpdateResult UpdateHashPrefixMapFromAdditions(
-      const ::google::protobuf::RepeatedPtrField<ThreatEntrySet>& additions,
-      HashPrefixMap* additions_map);
-
   // Merges the prefix map from the old store (|old_hash_prefix_map|) and the
   // update (additions_map) to populate the prefix map for the current store.
   // The indices in the |raw_removals| list, which may be NULL, are not merged.
@@ -341,6 +335,12 @@ class V4Store {
   // for the failure or reports success.
   StoreReadResult ReadFromDisk();
 
+  // Updates the |additions_map| with the additions received in the partial
+  // update from the server.
+  ApplyUpdateResult UpdateHashPrefixMapFromAdditions(
+      const ::google::protobuf::RepeatedPtrField<ThreatEntrySet>& additions,
+      HashPrefixMap* additions_map);
+
   // Writes the FULL_UPDATE |response| to disk as a V4StoreFileFormat proto.
   StoreWriteResult WriteToDisk(
       std::unique_ptr<ListUpdateResponse> response) const;