Introduce LiteralsArray to hide it's implementation.

src/factory.h

Index: src/factory.h
diff --git a/src/factory.h b/src/factory.h
index e044a1f47dc7706c78eab97023c10e8fba72b849..3e499c4fab714a81f09bef27c8bd64ce38578ef0 100644
--- a/src/factory.h
+++ b/src/factory.h
@@ -641,6 +641,10 @@ class Factory final {
   template <typename Spec>
   Handle<TypeFeedbackVector> NewTypeFeedbackVector(const Spec* spec);
 
+  Handle<LiteralsArray> NewLiteralsArray(Handle<TypeFeedbackVector> vector,
+                                         int number_of_literals,
+                                         PretenureFlag pretenure);
+
   // Allocates a new JSMessageObject object.
   Handle<JSMessageObject> NewJSMessageObject(MessageTemplate::Template message,
                                              Handle<Object> argument,