Serializer: support all alignment kinds.

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index 80eb5620a811dace8718ba2c876ada7b9cd7377f..ec48b324479b6bd90b66fd5af7c728f03e5ac804 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -3102,7 +3102,7 @@ AllocationResult Heap::AllocateWeakCell(HeapObject* value) {
   }
   result->set_map_no_write_barrier(weak_cell_map());
   WeakCell::cast(result)->initialize(value);
-  WeakCell::cast(result)->set_next(undefined_value(), SKIP_WRITE_BARRIER);
+  WeakCell::cast(result)->set_next(the_hole_value(), SKIP_WRITE_BARRIER);
   return result;
 }
 
@@ -3706,19 +3706,18 @@ AllocationResult Heap::AllocateByteArray(int length, PretenureFlag pretenure) {
 void Heap::CreateFillerObjectAt(Address addr, int size) {
   if (size == 0) return;
   HeapObject* filler = HeapObject::FromAddress(addr);
-  // At this point, we may be deserializing the heap from a snapshot, and
-  // none of the maps have been created yet and are NULL.
   if (size == kPointerSize) {
     filler->set_map_no_write_barrier(raw_unchecked_one_pointer_filler_map());
-    DCHECK(filler->map() == NULL || filler->map() == one_pointer_filler_map());
   } else if (size == 2 * kPointerSize) {
     filler->set_map_no_write_barrier(raw_unchecked_two_pointer_filler_map());
-    DCHECK(filler->map() == NULL || filler->map() == two_pointer_filler_map());
   } else {
     filler->set_map_no_write_barrier(raw_unchecked_free_space_map());
-    DCHECK(filler->map() == NULL || filler->map() == free_space_map());
     FreeSpace::cast(filler)->nobarrier_set_size(size);
   }
+  // At this point, we may be deserializing the heap from a snapshot, and
+  // none of the maps have been created yet and are NULL.
+  DCHECK((filler->map() == NULL && !deserialization_complete_) ||
+         filler->map()->IsMap());
 }