[heap] Enforce finalization of marking at heap limit when optimizing for memory usage.

src/heap/heap-inl.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_HEAP_HEAP_INL_H_
 #define V8_HEAP_HEAP_INL_H_
 
 #include <cmath>
 
 #include "src/base/platform/platform.h"
@@ skipping 366 matching lines @@
 
 bool Heap::InNewSpaceSlow(Address address) {
   return new_space_.ContainsSlow(address);
 }
 
 bool Heap::InOldSpaceSlow(Address address) {
   return old_space_->ContainsSlow(address);
 }
 
 bool Heap::OldGenerationAllocationLimitReached() {
-  if (!incremental_marking()->IsStopped()) return false;
+  if (!incremental_marking()->IsStopped() && !ShouldOptimizeForMemoryUsage()) {
+    return false;
+  }
   return OldGenerationSpaceAvailable() < 0;
 }
 
 template <PromotionMode promotion_mode>
 bool Heap::ShouldBePromoted(Address old_address, int object_size) {
   Page* page = Page::FromAddress(old_address);
   Address age_mark = new_space_.age_mark();
 
   if (promotion_mode == PROMOTE_MARKED) {
     MarkBit mark_bit = ObjectMarking::MarkBitFrom(old_address);
@@ skipping 381 matching lines @@
 
 void VerifySmisVisitor::VisitPointers(Object** start, Object** end) {
   for (Object** current = start; current < end; current++) {
     CHECK((*current)->IsSmi());
   }
 }
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_HEAP_INL_H_