Reverting r4703.

src/ia32/macro-assembler-ia32.h

Index: src/ia32/macro-assembler-ia32.h
===================================================================
--- src/ia32/macro-assembler-ia32.h	(revision 4703)
+++ src/ia32/macro-assembler-ia32.h	(working copy)
@@ -59,8 +59,8 @@
   // ---------------------------------------------------------------------------
   // GC Support
 
-  // For page containing |object| mark region covering |addr| dirty.
-  // RecordWriteHelper only works if the object is not in new
+  // Set the remebered set bit for an address which points into an
+  // object. RecordWriteHelper only works if the object is not in new
   // space.
   void RecordWriteHelper(Register object,
                          Register addr,
@@ -73,7 +73,7 @@
                   Condition cc,  // equal for new space, not_equal otherwise.
                   Label* branch);
 
-  // For page containing |object| mark region covering [object+offset] dirty.
+  // Set the remembered set bit for [object+offset].
   // object is the object being stored into, value is the object being stored.
   // If offset is zero, then the scratch register contains the array index into
   // the elements array represented as a Smi.