Change HistoryInfoMap to use unordered_map.

components/omnibox/browser/in_memory_url_index_types.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_OMNIBOX_BROWSER_IN_MEMORY_URL_INDEX_TYPES_H_
 #define COMPONENTS_OMNIBOX_BROWSER_IN_MEMORY_URL_INDEX_TYPES_H_
 
 #include <map>
 #include <set>
 #include <vector>
 
+#include "base/containers/hash_tables.h"
 #include "base/strings/string16.h"
 #include "components/history/core/browser/history_types.h"
 #include "url/gurl.h"
 
 // Matches within URL and Title Strings ----------------------------------------
 
 // Specifies where an omnibox term occurs within a string. Used for specifying
 // highlights in AutocompleteMatches (ACMatchClassifications) and to assist in
 // scoring a result.
 struct TermMatch {
@@ skipping 124 matching lines @@
   history::URLRow url_row;
 
   // This field gets filled in asynchronously after a visit.  As such,
   // it's almost always correct.  If it's wrong, it's likely to either
   // be empty (if this URL was recently added to the index) or
   // slightly out-of-date (one visit behind).
   VisitInfoVector visits;
 };
 
 // A map from history_id to the history's URL and title.
-typedef std::map<HistoryID, HistoryInfoMapValue> HistoryInfoMap;
+typedef base::hash_map<HistoryID, HistoryInfoMapValue> HistoryInfoMap;
 
 // A map from history_id to URL and page title word start metrics.
 struct RowWordStarts {
   RowWordStarts();
   ~RowWordStarts();
 
   // Clears both url_word_starts_ and title_word_starts_.
   void Clear();
 
   WordStarts url_word_starts_;
   WordStarts title_word_starts_;
 };
 typedef std::map<HistoryID, RowWordStarts> WordStartsMap;
 
 #endif  // COMPONENTS_OMNIBOX_BROWSER_IN_MEMORY_URL_INDEX_TYPES_H_