Enable preaging of code objects when --optimize-for-size.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index e5c1a2247986cd9553aa5ddd1d2aafb61ddd5dd9..eae23177a4716307c791707dc0621e0e69d26dfd 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -5147,7 +5147,9 @@ class Code: public HeapObject {
     CODE_AGE_LIST(DECLARE_CODE_AGE_ENUM)
     kAfterLastCodeAge,
     kLastCodeAge = kAfterLastCodeAge - 1,
-    kCodeAgeCount = kAfterLastCodeAge - 1
+    kCodeAgeCount = kAfterLastCodeAge - 1,
+    kPreAgedCodeAge = kQuinquagenarianCodeAge,
+    kIsOldCodeAge = kSexagenarianCodeAge
   };
 #undef DECLARE_CODE_AGE_ENUM
 
@@ -5158,6 +5160,7 @@ class Code: public HeapObject {
   static void MakeCodeAgeSequenceYoung(byte* sequence, Isolate* isolate);
   void MakeOlder(MarkingParity);
   static bool IsYoungSequence(byte* sequence);
+  static bool IsPreAgedSequence(byte* sequence);
   bool IsOld();
   int GetAge();