Remake of the load elimination fix made earlier (r18884).

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index c6f36bf63bdb3b4d31fba9c27b42bf8efff2f583..ab388280a8a0aa47a10ed7ce43e095e60b549cf4 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -5989,6 +5989,11 @@ class Map: public HeapObject {
   Map* FindUpdatedMap(int verbatim, int length, DescriptorArray* descriptors);
   Map* FindLastMatchMap(int verbatim, int length, DescriptorArray* descriptors);
 
+  inline int GetInObjectPropertyOffset(int index);
+  // Calculates index of the in-object property by offset. Values below zero
+  // correspond to accesses to the object header fields.
+  inline int GetInObjectPropertyIndex(int offset);
+
   int NumberOfFields();
 
   bool InstancesNeedRewriting(Map* target,