Revert of [heap] New heuristics for starting of incremental marking.

src/heap/incremental-marking.h

Index: src/heap/incremental-marking.h
diff --git a/src/heap/incremental-marking.h b/src/heap/incremental-marking.h
index c2290c4d8206ee39907d7d327baca35cb9e5db46..8990d0f3f14e5886fb167a51b629a0e9cde5756d 100644
--- a/src/heap/incremental-marking.h
+++ b/src/heap/incremental-marking.h
@@ -72,6 +72,8 @@
 
   bool CanBeActivated();
 
+  bool ShouldActivateEvenWithoutIdleNotification();
+
   bool WasActivated();
 
   void Start(GarbageCollectionReason gc_reason);
@@ -114,12 +116,6 @@
   // This is the upper bound for how many times we allow finalization of
   // incremental marking to be postponed.
   static const int kMaxIdleMarkingDelayCounter = 3;
-
-#ifndef DEBUG
-  static const intptr_t kActivationThreshold = 8 * MB;
-#else
-  static const intptr_t kActivationThreshold = 0;
-#endif
 
   void FinalizeSweeping();