Allow std::unordered_*.

chrome/browser/spellchecker/spellcheck_host_metrics.h

 // Copyright (c) 2011 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 CHROME_BROWSER_SPELLCHECKER_SPELLCHECK_HOST_METRICS_H_
 #define CHROME_BROWSER_SPELLCHECKER_SPELLCHECK_HOST_METRICS_H_
 
 #include <string>
 #include <vector>
 
 #include "base/containers/hash_tables.h"
+#include "base/strings/string16.h"
 #include "base/time/time.h"
 #include "base/timer/timer.h"
 
 // A helper object for recording spell-check related histograms.
 // This class encapsulates histogram names and metrics API.
 // This also carries a set of counters for collecting histograms
 // and a timer for making a periodical summary.
 //
 // We expect a user of SpellCheckHost class to instantiate this object,
 // and pass the metrics object to SpellCheckHost's factory method.
@@ skipping 63 matching lines @@
   int last_unique_word_count_;
 
   // Time when first spellcheck happened.
   base::TimeTicks start_time_;
   // Set of checked words in the hashed form.
   base::hash_set<std::string> checked_word_hashes_;
   base::RepeatingTimer recording_timer_;
 };
 
 #endif  // CHROME_BROWSER_SPELLCHECKER_SPELLCHECK_HOST_METRICS_H_