Reland "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 9c6a2a1690cdba36130ba3147302a84acf43d45d..5139c2177f8e1e85e50cec0ae70cc6ebcba0b20d 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -4622,10 +4622,23 @@ void Heap::ReduceNewSpaceSize() {
 }
 
 
+void Heap::FinalizeIncrementalMarkingIfComplete(const char* comment) {
+  if (FLAG_overapproximate_weak_closure && incremental_marking()->IsMarking() &&
+      (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(current_gc_flags_, 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) {
-  if (FLAG_overapproximate_weak_closure &&
+  if (FLAG_overapproximate_weak_closure && incremental_marking()->IsMarking() &&
       (incremental_marking()->IsReadyToOverApproximateWeakClosure() ||
        (!incremental_marking()->weak_closure_was_overapproximated() &&
         mark_compact_collector_.marking_deque()->IsEmpty() &&