Revert of Change WebContents::last_active_time_ to Time instead of Timeticks.

chrome/browser/chromeos/memory/oom_priority_manager.h

 // Copyright (c) 2012 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_CHROMEOS_MEMORY_OOM_PRIORITY_MANAGER_H_
 #define CHROME_BROWSER_CHROMEOS_MEMORY_OOM_PRIORITY_MANAGER_H_
 
 #include <utility>
 #include <vector>
 
@@ skipping 61 matching lines @@
 
   struct TabStats {
     TabStats();
     ~TabStats();
     bool is_app;  // browser window is an app
     bool is_reloadable_ui;  // Reloadable web UI page, like NTP or Settings.
     bool is_playing_audio;
     bool is_pinned;
     bool is_selected;  // selected in the currently active browser window
     bool is_discarded;
-    base::Time last_active;
+    base::TimeTicks last_active;
     base::ProcessHandle renderer_handle;
     int child_process_host_id;
     base::string16 title;
     int64 tab_contents_id;  // unique ID per WebContents
   };
   typedef std::vector<TabStats> TabStatsList;
 
   // Returns true if the |url| represents an internal Chrome web UI page that
   // can be easily reloaded and hence makes a good choice to discard.
   static bool IsReloadableUI(const GURL& url);
@@ skipping 91 matching lines @@
   // Whether a tab discard event has occurred during the last time interval,
   // used for statistics normalized by usage.
   bool recent_tab_discard_;
 
   DISALLOW_COPY_AND_ASSIGN(OomPriorityManager);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_MEMORY_OOM_PRIORITY_MANAGER_H_