[turbofan] Implement the implicit ToObject for property access.

src/crankshaft/hydrogen.cc

Index: src/crankshaft/hydrogen.cc
diff --git a/src/crankshaft/hydrogen.cc b/src/crankshaft/hydrogen.cc
index 17fb0afc05d181c1adbe03a7eaac486dabb436c2..555291f588efac8062d74813d2be691a32455341 100644
--- a/src/crankshaft/hydrogen.cc
+++ b/src/crankshaft/hydrogen.cc
@@ -6510,9 +6510,12 @@ bool HOptimizedGraphBuilder::PropertyAccessInfo::CanAccessAsMonomorphic(
 
 
 Handle<Map> HOptimizedGraphBuilder::PropertyAccessInfo::map() {
-  JSFunction* ctor = IC::GetRootConstructor(
-      *map_, current_info()->closure()->context()->native_context());
-  if (ctor != NULL) return handle(ctor->initial_map());
+  Handle<JSFunction> ctor;
+  if (Map::GetConstructorFunction(
+          map_, handle(current_info()->closure()->context()->native_context()))
+          .ToHandle(&ctor)) {
+    return handle(ctor->initial_map());
+  }
   return map_;
 }