Enable preaging of code objects when --optimize-for-size.

src/assembler.cc

Index: src/assembler.cc
diff --git a/src/assembler.cc b/src/assembler.cc
index 6581aa1305a459fdc8c90b31d0a9faabf9f78169..06f9704265d43ef3edbe113294d95fd93986babe 100644
--- a/src/assembler.cc
+++ b/src/assembler.cc
@@ -1087,6 +1087,13 @@ ExternalReference ExternalReference::get_make_code_young_function(
 }
 
 
+ExternalReference ExternalReference::get_mark_code_as_executed_function(
+    Isolate* isolate) {
+  return ExternalReference(Redirect(
+      isolate, FUNCTION_ADDR(Code::MarkCodeAsExecuted)));
+}
+
+
 ExternalReference ExternalReference::date_cache_stamp(Isolate* isolate) {
   return ExternalReference(isolate->date_cache()->stamp_address());
 }