Introduce FieldIndex to unify and abstract property/field offset

src/property.cc

 // Copyright 2014 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.
 
 #include "src/property.h"
 
 #include "src/handles-inl.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 29 matching lines @@
       PrintF(out, " -entry = %d", GetDictionaryEntry());
       break;
     case CONSTANT:
       PrintF(out, " -type = constant\n");
       PrintF(out, " -value:\n");
       GetConstant()->Print(out);
       PrintF(out, "\n");
       break;
     case FIELD:
       PrintF(out, " -type = field\n");
-      PrintF(out, " -index = %d\n", GetFieldIndex().field_index());
+      PrintF(out, " -index = %d\n",
+             GetFieldIndex().property_index());
       PrintF(out, " -field type:\n");
       GetFieldType()->TypePrint(out);
       break;
     case CALLBACKS:
       PrintF(out, " -type = call backs\n");
       PrintF(out, " -callback object:\n");
       GetCallbackObject()->Print(out);
       break;
     case HANDLER:
       PrintF(out, " -type = lookup proxy\n");
@@ skipping 10 matching lines @@
 
 void Descriptor::Print(FILE* out) {
   PrintF(out, "Descriptor ");
   GetKey()->ShortPrint(out);
   PrintF(out, " @ ");
   GetValue()->ShortPrint(out);
 }
 #endif
 
 } }  // namespace v8::internal