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

src/assembler.h

Index: src/assembler.h
diff --git a/src/assembler.h b/src/assembler.h
index 12200740a0becb3ff604b6622be73f73226badfc..ef5c11242ed2c2aff1fe458131474575765b4e83 100644
--- a/src/assembler.h
+++ b/src/assembler.h
@@ -402,6 +402,7 @@ class RelocInfo BASE_EMBEDDED {
   INLINE(Handle<Cell> target_cell_handle());
   INLINE(void set_target_cell(Cell* cell,
                               WriteBarrierMode mode = UPDATE_WRITE_BARRIER));
+  INLINE(Handle<Object> code_age_stub_handle(Assembler* origin));
   INLINE(Code* code_age_stub());
   INLINE(void set_code_age_stub(Code* stub));
 
@@ -728,6 +729,7 @@ class ExternalReference BASE_EMBEDDED {
   static ExternalReference date_cache_stamp(Isolate* isolate);
 
   static ExternalReference get_make_code_young_function(Isolate* isolate);
+  static ExternalReference get_mark_code_as_executed_function(Isolate* isolate);
 
   // Deoptimization support.
   static ExternalReference new_deoptimizer_function(Isolate* isolate);