Fix object initialization when slack tracking for it's map is still enabled.

src/ia32/macro-assembler-ia32.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_IA32_MACRO_ASSEMBLER_IA32_H_
 #define V8_IA32_MACRO_ASSEMBLER_IA32_H_
 
 #include "src/assembler.h"
 #include "src/bailout-reason.h"
 #include "src/frames.h"
@@ skipping 701 matching lines @@
                                    Register scratch2, Label* gc_required);
 
   // Copy memory, byte-by-byte, from source to destination.  Not optimized for
   // long or aligned copies.
   // The contents of index and scratch are destroyed.
   void CopyBytes(Register source,
                  Register destination,
                  Register length,
                  Register scratch);
 
-  // Initialize fields with filler values.  Fields starting at |start_offset|
-  // not including end_offset are overwritten with the value in |filler|.  At
-  // the end the loop, |start_offset| takes the value of |end_offset|.
-  void InitializeFieldsWithFiller(Register start_offset,
-                                  Register end_offset,
-                                  Register filler);
+  // Initialize fields with filler values.  Fields starting at |current_address|
+  // not including |end_address| are overwritten with the value in |filler|.  At
+  // the end the loop, |current_address| takes the value of |end_address|.
+  void InitializeFieldsWithFiller(Register current_address,
+                                  Register end_address, Register filler);
 
   // ---------------------------------------------------------------------------
   // Support functions.
 
   // Check a boolean-bit of a Smi field.
   void BooleanBitTest(Register object, int field_offset, int bit_index);
 
   // Check if result is zero and op is negative.
   void NegativeZeroTest(Register result, Register op, Label* then_label);
 
@@ skipping 395 matching lines @@
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_IA32_MACRO_ASSEMBLER_IA32_H_