flat containers prototype

components/omnibox/browser/url_index_private_data.h

Index: components/omnibox/browser/url_index_private_data.h
diff --git a/components/omnibox/browser/url_index_private_data.h b/components/omnibox/browser/url_index_private_data.h
index 100692cd7b44e63de9bfbc2b01c3501a6e2bbd95..c1c7f4523b45074d146eedf041d98c54b2087fb5 100644
--- a/components/omnibox/browser/url_index_private_data.h
+++ b/components/omnibox/browser/url_index_private_data.h
@@ -184,7 +184,8 @@ class URLIndexPrivateData
     HistoryIDSet history_id_set_;
     bool used_;  // True if this item has been used for the current term search.
   };
-  typedef std::map<base::string16, SearchTermCacheItem> SearchTermCacheMap;
+  typedef base::flat_map<base::string16, SearchTermCacheItem>
+      SearchTermCacheMap;
 
   // A helper class which performs the final filter on each candidate
   // history URL match, inserting accepted matches into |scored_matches_|.