chromeos: Set a least score to the currently focused tab so that it is not selected

chrome/browser/oom_priority_manager.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_OOM_PRIORITY_MANAGER_H_
 #define CHROME_BROWSER_OOM_PRIORITY_MANAGER_H_
 
 #include <vector>
 
 #include "base/hash_tables.h"
@@ skipping 43 matching lines @@
     base::ProcessHandle renderer_handle;
     string16 title;
   };
   typedef std::vector<RendererStats> StatsList;
   typedef base::hash_map<base::ProcessHandle, int> ProcessScoreMap;
 
   // Posts DoAdjustOomPriorities task to the file thread.  Called when
   // the timer fires.
   void AdjustOomPriorities();
 
+  // Posts AdjustFocusedTabScore task to the file thread.
+  void OnFocusTabScoreAdjustmentTimeout();
+
   // Called by AdjustOomPriorities.  Runs on the file thread.
   void DoAdjustOomPriorities();
 
+  // Called when a tab comes into focus. Runs on the file thread.
+  // Sets the score of only the currently focused tab to the least value.
+  void AdjustFocusedTabScore();
+
   static bool CompareRendererStats(RendererStats first, RendererStats second);
 
   virtual void Observe(int type,
                        const NotificationSource& source,
                        const NotificationDetails& details);
 
   base::RepeatingTimer<OomPriorityManager> timer_;
+  base::OneShotTimer<OomPriorityManager> focus_tab_score_adjust_timer_;
   // renderer_stats_ is used on both UI and file threads.
   base::Lock renderer_stats_lock_;
   StatsList renderer_stats_;
-  // map maintaining the process - oom_score map.
+  // This lock is for pid_to_oom_score_ and focus_tab_pid_.
   base::Lock pid_to_oom_score_lock_;
+  // map maintaining the process - oom_score mapping.
   ProcessScoreMap pid_to_oom_score_;
   NotificationRegistrar registrar_;
+  base::ProcessHandle focused_tab_pid_;
 
   DISALLOW_COPY_AND_ASSIGN(OomPriorityManager);
 };
 
 }  // namespace browser
 
 DISABLE_RUNNABLE_METHOD_REFCOUNT(browser::OomPriorityManager);
 
 #endif  // CHROME_BROWSER_OOM_PRIORITY_MANAGER_H_