[serializer] reserve maps one by one to avoid fragmentation.

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 736 matching lines @@
   inline HeapState gc_state() { return gc_state_; }
 
   inline bool IsInGCPostProcessing() { return gc_post_processing_depth_ > 0; }
 
   // If an object has an AllocationMemento trailing it, return it, otherwise
   // return NULL;
   template <FindMementoMode mode>
   inline AllocationMemento* FindAllocationMemento(HeapObject* object);
 
   // Returns false if not able to reserve.
-  bool ReserveSpace(Reservation* reservations);
+  bool ReserveSpace(Reservation* reservations, List<Address>* maps);
 
   void SetEmbedderHeapTracer(EmbedderHeapTracer* tracer);
 
   bool UsingEmbedderHeapTracer();
 
   void TracePossibleWrapper(JSObject* js_object);
 
   void RegisterExternallyReferencedObject(Object** object);
 
   //
@@ skipping 1940 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_