R=jkummerow@chromium.org

src/heap.h

Index: src/heap.h
diff --git a/src/heap.h b/src/heap.h
index 3116895c625eeafb9d042b44aaadba77276c9360..5cc7c0cc21b56b70cdaac0ab16492ec6b7edf9ed 100644
--- a/src/heap.h
+++ b/src/heap.h
@@ -1377,6 +1377,7 @@ class Heap {
   void CheckNewSpaceExpansionCriteria();
 
   inline void IncrementYoungSurvivorsCounter(int survived) {
+    ASSERT(survived >= 0);
     young_survivors_after_last_gc_ = survived;
     survived_since_last_expansion_ += survived;
   }
@@ -1424,6 +1425,7 @@ class Heap {
 
   // Returns the size of objects residing in non new spaces.
   intptr_t PromotedSpaceSize();
+  intptr_t PromotedSpaceSizeOfObjects();
 
   double total_regexp_code_generated() { return total_regexp_code_generated_; }
   void IncreaseTotalRegexpCodeGenerated(int size) {
@@ -1772,11 +1774,13 @@ class Heap {
 
   enum SurvivalRateTrend { INCREASING, STABLE, DECREASING, FLUCTUATING };
 
-  static const int kYoungSurvivalRateThreshold = 90;
+  static const int kYoungSurvivalRateHighThreshold = 90;
+  static const int kYoungSurvivalRateLowThreshold = 10;
   static const int kYoungSurvivalRateAllowedDeviation = 15;
 
   int young_survivors_after_last_gc_;
   int high_survival_rate_period_length_;
+  int low_survival_rate_period_length_;
   double survival_rate_;
   SurvivalRateTrend previous_survival_rate_trend_;
   SurvivalRateTrend survival_rate_trend_;
@@ -1809,18 +1813,28 @@ class Heap {
     }
   }
 
-  bool IsIncreasingSurvivalTrend() {
-    return survival_rate_trend() == INCREASING;
+  bool IsStableOrDecreasingSurvivalTrend() {
+    switch (survival_rate_trend()) {
+      case STABLE:
+      case DECREASING:
+        return true;
+      default:
+        return false;
+    }
   }
 
-  bool IsDecreasingSurvivalTrend() {
-    return survival_rate_trend() == DECREASING;
+  bool IsIncreasingSurvivalTrend() {
+    return survival_rate_trend() == INCREASING;
   }
 
   bool IsHighSurvivalRate() {
     return high_survival_rate_period_length_ > 0;
   }
 
+  bool IsLowSurvivalRate() {
+    return low_survival_rate_period_length_ > 0;
+  }
+
   void SelectScavengingVisitorsTable();
 
   static const int kInitialSymbolTableSize = 2048;