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

src/hydrogen.cc

 // Copyright 2013 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 "hydrogen.h"
 
 #include <algorithm>
 
 #include "v8.h"
 #include "allocation-site-scopes.h"
@@ skipping 8528 matching lines @@
   CHECK_ALIVE(VisitExpressions(expr->arguments()));
 
   if (FLAG_inline_construct &&
       expr->IsMonomorphic() &&
       IsAllocationInlineable(expr->target())) {
     Handle<JSFunction> constructor = expr->target();
     HValue* check = Add<HCheckValue>(function, constructor);
 
     // 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.
     ASSERT(constructor->has_initial_map());
     Handle<Map> initial_map(constructor->initial_map());
     int instance_size = initial_map->instance_size();
     ASSERT(initial_map->InitialPropertiesLength() == 0);
 
     // Allocate an instance of the implicit receiver object.
     HValue* size_in_bytes = Add<HConstant>(instance_size);
@@ skipping 3240 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal