[runtime] Remove specific Descriptor subclasses and add respective factory methods instead.

src/property.cc

Index: src/property.cc
diff --git a/src/property.cc b/src/property.cc
index a4e0d67102cb12c2b1eb00176709d4bc27b2f38a..28a2374453b75d5a06b41531bc194039a6ba7300 100644
--- a/src/property.cc
+++ b/src/property.cc
@@ -21,11 +21,12 @@ std::ostream& operator<<(std::ostream& os,
   return os;
 }
 
-DataDescriptor::DataDescriptor(Handle<Name> key, int field_index,
-                               PropertyAttributes attributes,
-                               Representation representation)
-    : Descriptor(key, FieldType::Any(key->GetIsolate()), attributes, DATA,
-                 representation, field_index) {}
+Descriptor Descriptor::DataField(Handle<Name> key, int field_index,
+                                 PropertyAttributes attributes,
+                                 Representation representation) {
+  return Descriptor(key, FieldType::Any(key->GetIsolate()), attributes, DATA,
+                    representation, field_index);
+}
 
 struct FastPropertyDetails {
   explicit FastPropertyDetails(const PropertyDetails& v) : details(v) {}