Make sure that memory reducer makes progress in incremental marking

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index e37c9f6b11de8b333743e8f296486d3561721013..4445665846f2a7d5ffb7cf064b02d444e0883246 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -4770,6 +4770,19 @@ void Heap::ReduceNewSpaceSize() {
 }
 
 
+void Heap::FinalizeIncrementalMarkingIfComplete(const char* comment) {
+  if (FLAG_overapproximate_weak_closure &&
+      (incremental_marking()->IsReadyToOverApproximateWeakClosure() ||
+       (!incremental_marking()->weak_closure_was_overapproximated() &&
+        mark_compact_collector_.marking_deque()->IsEmpty()))) {
+    OverApproximateWeakClosure(comment);
+  } else if (incremental_marking()->IsComplete() ||
+             (mark_compact_collector_.marking_deque()->IsEmpty())) {
+    CollectAllGarbage(kNoGCFlags, comment);
+  }
+}
+
+
 bool Heap::TryFinalizeIdleIncrementalMarking(
     double idle_time_in_ms, size_t size_of_objects,
     size_t final_incremental_mark_compact_speed_in_bytes_per_ms) {