Make the speed of incrmental marking depend also on the rate

src/heap.cc

Index: src/heap.cc
===================================================================
--- src/heap.cc	(revision 12583)
+++ src/heap.cc	(working copy)
@@ -5127,7 +5127,8 @@
   // The size factor is in range [5..250]. The numbers here are chosen from
   // experiments. If you changes them, make sure to test with
   // chrome/performance_ui_tests --gtest_filter="GeneralMixMemoryTest.*
-  intptr_t step_size = size_factor * IncrementalMarking::kAllocatedThreshold;
+  intptr_t step_size =
+      size_factor * IncrementalMarking::kIncrementalMarkingThreshold;
 
   if (contexts_disposed_ > 0) {
     if (hint >= kMaxHint) {