Introduce LiteralsArray to hide it's implementation.

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 53c5fec01faaf13708a52de83fc4971bf7ad15d0..ad091301ff91eaf37e337584b536aa90c54b28fd 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -10157,7 +10157,7 @@ void SharedFunctionInfo::AddSharedCodeToOptimizedCodeMap(
 
 void SharedFunctionInfo::AddToOptimizedCodeMap(
     Handle<SharedFunctionInfo> shared, Handle<Context> native_context,
-    Handle<HeapObject> code, Handle<FixedArray> literals,
+    Handle<HeapObject> code, Handle<LiteralsArray> literals,
     BailoutId osr_ast_id) {
   Isolate* isolate = shared->GetIsolate();
   DCHECK(*code == isolate->heap()->undefined_value() ||
@@ -11347,7 +11347,7 @@ CodeAndLiterals SharedFunctionInfo::SearchOptimizedCodeMap(
       DCHECK_LE(entry + kEntryLength, code_map->length());
       Object* code = code_map->get(entry + kCachedCodeOffset);
       result = {code->IsUndefined() ? nullptr : Code::cast(code),
-                FixedArray::cast(code_map->get(entry + kLiteralsOffset))};
+                LiteralsArray::cast(code_map->get(entry + kLiteralsOffset))};
     }
   }
   if (FLAG_trace_opt && !optimized_code_map()->IsSmi() &&