Consolidate code monitoring low memory kills and OOM kills to MemoryKillsMonitor on ChromeOS.

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 <utility>
 #include <vector>
@@ skipping 79 matching lines @@
   // Get debugd client instance.
   virtual chromeos::DebugDaemonClient* GetDebugDaemonClient();
 
  private:
   FRIEND_TEST_ALL_PREFIXES(TabManagerDelegateTest, CandidatesSorted);
   FRIEND_TEST_ALL_PREFIXES(TabManagerDelegateTest, KillMultipleProcesses);
   FRIEND_TEST_ALL_PREFIXES(TabManagerDelegateTest, SetOomScoreAdj);
 
   class Candidate;
   class FocusedProcess;
-  class UmaReporter;
 
   friend std::ostream& operator<<(std::ostream& out,
                                   const Candidate& candidate);
 
   // content::NotificationObserver:
   void Observe(int type,
                const content::NotificationSource& source,
                const content::NotificationDetails& details) override;
 
   // Pair to hold child process host id and ProcessHandle.
@@ skipping 51 matching lines @@
   // Holds the info of the newly focused tab or app. Its OOM score would be
   // adjusted when |focus_process_score_adjust_timer_| is expired.
   std::unique_ptr<FocusedProcess> focused_process_;
 
   // Map maintaining the process handle - oom_score mapping.
   ProcessScoreMap oom_score_map_;
 
   // Util for getting system memory status.
   std::unique_ptr<TabManagerDelegate::MemoryStat> mem_stat_;
 
-  // Reports UMA histograms.
-  std::unique_ptr<UmaReporter> uma_;
-
   // Weak pointer factory used for posting tasks to other threads.
   base::WeakPtrFactory<TabManagerDelegate> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(TabManagerDelegate);
 };
 
 // On ARC enabled machines, either a tab or an app could be a possible
 // victim of low memory kill process. This is a helper class which holds a
 // pointer to an app or a tab (but not both) to facilitate prioritizing the
 // victims.
@@ skipping 48 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_