Ensure black and gray objects are kept around by scavenger

src/heap/heap.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_H_
 #define V8_HEAP_HEAP_H_
 
 #include <cmath>
 #include <map>
 
@@ skipping 1068 matching lines @@
 
   // Iterate pointers of promoted objects.
   void IteratePromotedObject(HeapObject* target, int size,
                              bool was_marked_black,
                              ObjectSlotCallback callback);
 
   void IteratePromotedObjectPointers(HeapObject* object, Address start,
                                      Address end, bool record_slots,
                                      ObjectSlotCallback callback);
 
+  // Scavenges all objects in the from_space marked by MarkCompact while
+  // immediately promoting them.
+  void PromoteMarkedObjects();
+
   // ===========================================================================
   // Store buffer API. =========================================================
   // ===========================================================================
 
   // Write barrier support for object[offset] = o;
   inline void RecordWrite(Object* object, int offset, Object* o);
   inline void RecordFixedArrayElements(FixedArray* array, int offset,
                                        int length);
 
   Address* store_buffer_top_address() { return store_buffer()->top_address(); }
@@ skipping 1563 matching lines @@
   friend class LargeObjectSpace;
   friend class NewSpace;
   friend class PagedSpace;
   DISALLOW_COPY_AND_ASSIGN(AllocationObserver);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_HEAP_H_