Explicitly track whether incremental marking was activated

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index b73a63e8c12faa9fa27f83a4ffdb8546b84bb242..6502de3a9b43ff96f9c0cda1f9d7217222246331 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -1210,15 +1210,22 @@ void Heap::MarkCompact() {
 
   LOG(isolate_, ResourceEvent("markcompact", "end"));
 
+  MarkCompactEpilogue();
+
+  if (FLAG_allocation_site_pretenuring) {
+    EvaluateOldSpaceLocalPretenuring(size_of_objects_before_gc);
+  }
+}
+
+
+void Heap::MarkCompactEpilogue() {
   gc_state_ = NOT_IN_GC;
 
   isolate_->counters()->objs_since_last_full()->Set(0);
 
   flush_monomorphic_ics_ = false;
 
-  if (FLAG_allocation_site_pretenuring) {
-    EvaluateOldSpaceLocalPretenuring(size_of_objects_before_gc);
-  }
+  incremental_marking()->Epilogue();
 }