[serializer] Tenure young large object in the serializer.

Bug: chromium:852420
Change-Id: I54d1708991468bb062d9e7b246e724594f252e5e
Reviewed-on: https://chromium-review.googlesource.com/c/1346369
Commit-Queue: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57686}

src/snapshot/serializer-allocator.cc

@@ -42,6 +42,8 @@ SerializerReference SerializerAllocator::Allocate(AllocationSpace space,
 
   // Maps are allocated through AllocateMap.
   DCHECK_NE(MAP_SPACE, space);
+  // We tenure large object allocations.
+  DCHECK_NE(NEW_LO_SPACE, space);
 
   uint32_t old_chunk_size = pending_chunk_[space];
   uint32_t new_chunk_size = old_chunk_size + size;

src/snapshot/serializer.cc

@@ -596,7 +596,10 @@ void Serializer::ObjectSerializer::SerializeObject() {
   Map map = object_->map();
   AllocationSpace space =
       MemoryChunk::FromAddress(object_->address())->owner()->identity();
-  DCHECK(space != NEW_LO_SPACE);
+  // Young generation large objects are tenured.
+  if (space == NEW_LO_SPACE) {
+    space = LO_SPACE;
+  }
   SerializePrologue(space, size, map);
 
   // Serialize the rest of the object.