Add out of memory stats for graphics memory, discards per minute

chrome/browser/chromeos/memory/oom_priority_manager.h

Index: chrome/browser/chromeos/memory/oom_priority_manager.h
diff --git a/chrome/browser/chromeos/memory/oom_priority_manager.h b/chrome/browser/chromeos/memory/oom_priority_manager.h
index 2b988191b68c3edc3db8429d04812fe205654361..a6cf70495312c6b878b9417c9f724176a1d09fb5 100644
--- a/chrome/browser/chromeos/memory/oom_priority_manager.h
+++ b/chrome/browser/chromeos/memory/oom_priority_manager.h
@@ -42,6 +42,9 @@ class OomPriorityManager : public content::NotificationObserver {
   // Number of discard events since Chrome started.
   int discard_count() const { return discard_count_; }
 
+  // See member comment.
+  bool recent_tab_discard() const { return recent_tab_discard_; }
+
   void Start();
   void Stop();
 
@@ -91,6 +94,10 @@ class OomPriorityManager : public content::NotificationObserver {
   // to manually test the system.
   void RecordDiscardStatistics();
 
+  // Record whether we ran out of memory during a recent time interval.
+  // This allows us to normalize low memory statistics versus usage.
+  void RecordRecentTabDiscard();
+
   // Purges data structures in the browser that can be easily recomputed.
   void PurgeBrowserMemory();
 
@@ -119,6 +126,7 @@ class OomPriorityManager : public content::NotificationObserver {
 
   base::RepeatingTimer<OomPriorityManager> timer_;
   base::OneShotTimer<OomPriorityManager> focus_tab_score_adjust_timer_;
+  base::RepeatingTimer<OomPriorityManager> recent_tab_discard_timer_;
   content::NotificationRegistrar registrar_;
 
   // This lock is for pid_to_oom_score_ and focus_tab_pid_.
@@ -146,6 +154,10 @@ class OomPriorityManager : public content::NotificationObserver {
   // Number of times we have discarded a tab, for statistics.
   int discard_count_;
 
+  // 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);
 };