TabManager: Set OOM scores via a new debugd interface on ChromeOS.

chrome/browser/memory/tab_manager_delegate_chromeos.h

Index: chrome/browser/memory/tab_manager_delegate_chromeos.h
diff --git a/chrome/browser/memory/tab_manager_delegate_chromeos.h b/chrome/browser/memory/tab_manager_delegate_chromeos.h
index 0b4fa54f960229b554ba18c5580b701637dcd95c..bb202a5632b45fec18afd1a06518b17c02174ce0 100644
--- a/chrome/browser/memory/tab_manager_delegate_chromeos.h
+++ b/chrome/browser/memory/tab_manager_delegate_chromeos.h
@@ -46,10 +46,6 @@ enum class ProcessType {
 
 // The Chrome OS TabManagerDelegate is responsible for keeping the
 // renderers' scores up to date in /proc/<pid>/oom_score_adj.
-//
-// Note that AdjustOomPriorities will be called on the UI thread by
-// TabManager, but the actual work will take place on the file thread
-// (see implementation of AdjustOomPriorities).
 class TabManagerDelegate
     : public arc::InstanceHolder<arc::mojom::ProcessInstance>::Observer,
       public aura::client::ActivationChangeObserver,
@@ -89,12 +85,6 @@ class TabManagerDelegate
   void AdjustOomPriorities(const TabStatsList& tab_list);
 
  protected:
-  // Sets oom_score_adj for a list of tabs.
-  // This is a delegator to to SetOomScoreAdjForTabsOnFileThread(),
-  // also as a seam for unit test.
-  virtual void SetOomScoreAdjForTabs(
-      const std::vector<std::pair<base::ProcessHandle, int>>& entries);
-
   // Kills an Arc process. Returns true if the kill request is successfully sent
   // to Android. Virtual for unit testing.
   virtual bool KillArcProcess(const int nspid);
@@ -131,7 +121,7 @@ class TabManagerDelegate
       const TabStatsList& tab_list,
       const std::vector<arc::ArcProcess>& arc_processes);
 
-  // Posts AdjustFocusedTabScore task to the file thread.
+  // Sets OOM score for the focused tab.
   void OnFocusTabScoreAdjustmentTimeout();
 
   // Kills a process after getting all info of tabs and apps.
@@ -142,9 +132,6 @@ class TabManagerDelegate
   void AdjustOomPriorities(const TabStatsList& tab_list,
                            const std::vector<arc::ArcProcess>& arc_processes);
 
-  // Sets the score of the focused tab to the least value.
-  void AdjustFocusedTabScoreOnFileThread();
-
   // Sets a newly focused tab the highest priority process if it wasn't.
   void AdjustFocusedTabScore(base::ProcessHandle pid);
 
@@ -153,13 +140,6 @@ class TabManagerDelegate
       const TabStatsList& tab_list,
       const std::vector<arc::ArcProcess>& arc_processes);
 
-  // Sets oom_score_adj of an ARC app.
-  void SetOomScoreAdjForApp(int nspid, int score);
-
-  // Sets oom_score_adj for a list of tabs on the file thread.
-  void SetOomScoreAdjForTabsOnFileThread(
-      const std::vector<std::pair<base::ProcessHandle, int>>& entries);
-
   // Sets OOM score for processes in the range [|rbegin|, |rend|) to integers
   // distributed evenly in [|range_begin|, |range_end|).
   // The new score is set in |new_map|.
@@ -186,10 +166,7 @@ class TabManagerDelegate
   // adjusted when |focus_process_score_adjust_timer_| is expired.
   std::unique_ptr<FocusedProcess> focused_process_;
 
-  // This lock is for |oom_score_map_|.
-  base::Lock oom_score_lock_;
-  // Map maintaining the process handle - oom_score mapping. Behind
-  // |oom_score_lock_|.
+  // Map maintaining the process handle - oom_score mapping.
   ProcessScoreMap oom_score_map_;
 
   // Util for getting system memory satatus.