Remove uses of base::hash_map from //chrome

chrome/browser/memory/tab_manager_delegate_chromeos.h

 // Copyright 2015 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_MEMORY_TAB_MANAGER_DELEGATE_CHROMEOS_H_
 #define CHROME_BROWSER_MEMORY_TAB_MANAGER_DELEGATE_CHROMEOS_H_
 
 #include <memory>
 #include <string>
 #include <utility>
 #include <vector>
 
-#include "base/containers/hash_tables.h"
+#include "base/containers/flat_map.h"
 #include "base/gtest_prod_util.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/process/process.h"
 #include "base/timer/timer.h"
 #include "chrome/browser/chromeos/arc/process/arc_process.h"
 #include "chrome/browser/memory/tab_manager.h"
 #include "chrome/browser/memory/tab_stats.h"
 #include "chrome/browser/ui/browser_list_observer.h"
@@ skipping 96 matching lines @@
 
   // content::NotificationObserver:
   void Observe(int type,
                const content::NotificationSource& source,
                const content::NotificationDetails& details) override;
 
   // Pair to hold child process host id and ProcessHandle.
   typedef std::pair<int, base::ProcessHandle> ProcessInfo;
 
   // Cache OOM scores in memory.
-  typedef base::hash_map<base::ProcessHandle, int> ProcessScoreMap;
+  typedef base::flat_map<base::ProcessHandle, int> ProcessScoreMap;
 
   // A map from an ARC process name to a monotonic timestamp when it's killed.
-  typedef base::hash_map<std::string, base::TimeTicks> KilledArcProcessesMap;
+  typedef base::flat_map<std::string, base::TimeTicks> KilledArcProcessesMap;
 
   // Get the list of candidates to kill, sorted by descending importance.
   static std::vector<Candidate> GetSortedCandidates(
       const TabStatsList& tab_list,
       const std::vector<arc::ArcProcess>& arc_processes);
 
   // Sets OOM score for the focused tab.
   void OnFocusTabScoreAdjustmentTimeout();
 
   // Kills a process after getting all info of tabs and apps.
@@ skipping 125 matching lines @@
   // reported if available memory is under the number.
   static int LowMemoryMarginKB();
 
   // Reads in an integer.
   static int ReadIntFromFile(const char* file_name, int default_val);
 };
 
 }  // namespace memory
 
 #endif  // CHROME_BROWSER_MEMORY_TAB_MANAGER_DELEGATE_CHROMEOS_H_