Update V8 to r3121 as required for WebKit update.

Change-Id: Ic53e0aef9a9eb9b71ee7d25a8aef61520bba899c
diff --git a/src/spaces-inl.h b/src/spaces-inl.h
index da72497..847bb9a 100644
--- a/src/spaces-inl.h
+++ b/src/spaces-inl.h
@@ -360,6 +360,13 @@
   return obj;
 }
 
+
+bool FreeListNode::IsFreeListNode(HeapObject* object) {
+  return object->map() == Heap::raw_unchecked_byte_array_map()
+      || object->map() == Heap::raw_unchecked_one_pointer_filler_map()
+      || object->map() == Heap::raw_unchecked_two_pointer_filler_map();
+}
+
 } }  // namespace v8::internal
 
 #endif  // V8_SPACES_INL_H_