Optimize write barrier of map-only elements transitions

src/assembler.h

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // All Rights Reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 // - Redistributions of source code must retain the above copyright notice,
 // this list of conditions and the following disclaimer.
 //
@@ skipping 638 matching lines @@
   static ExternalReference address_of_uint8_max_value();
   static ExternalReference address_of_negative_infinity();
   static ExternalReference address_of_canonical_non_hole_nan();
   static ExternalReference address_of_the_hole_nan();
 
   static ExternalReference math_sin_double_function(Isolate* isolate);
   static ExternalReference math_cos_double_function(Isolate* isolate);
   static ExternalReference math_tan_double_function(Isolate* isolate);
   static ExternalReference math_log_double_function(Isolate* isolate);
 
+  static ExternalReference page_flags(Page* page);
+
   Address address() const {return reinterpret_cast<Address>(address_);}
 
 #ifdef ENABLE_DEBUGGER_SUPPORT
   // Function Debug::Break()
   static ExternalReference debug_break(Isolate* isolate);
 
   // Used to check if single stepping is enabled in generated code.
   static ExternalReference debug_step_in_fp_address(Isolate* isolate);
 #endif
 
@@ skipping 207 matching lines @@
  public:
   NullCallWrapper() { }
   virtual ~NullCallWrapper() { }
   virtual void BeforeCall(int call_size) const { }
   virtual void AfterCall() const { }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_ASSEMBLER_H_