Inobject slack tracking is done on a per-closure basis instead of per-shared info basis.

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 46f893d26afa6e6ad2a883cae59ce1209a07fa75..58b4b8333aac0d6c3420a50c736e397f5e652ce6 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -8546,8 +8546,8 @@ void HOptimizedGraphBuilder::VisitCallNew(CallNew* expr) {
 
     // Force completion of inobject slack tracking before generating
     // allocation code to finalize instance size.
-    if (constructor->shared()->IsInobjectSlackTrackingInProgress()) {
-      constructor->shared()->CompleteInobjectSlackTracking();
+    if (constructor->IsInobjectSlackTrackingInProgress()) {
+      constructor->CompleteInobjectSlackTracking();
     }
 
     // Calculate instance size from initial map of constructor.