Limit the number of transitions allowed per hidden class.

src/transitions-inl.h

Index: src/transitions-inl.h
diff --git a/src/transitions-inl.h b/src/transitions-inl.h
index a16eb4477cd60c1486ed5b697f257d619d9e1b05..08cb6476bf02df72bda4a1695e823a4147660f13 100644
--- a/src/transitions-inl.h
+++ b/src/transitions-inl.h
@@ -154,6 +154,15 @@ void TransitionArray::NoIncrementalWriteBarrierSet(int transition_number,
 }
 
 
+void TransitionArray::SetNumberOfTransitions(int number_of_transitions) {
+  if (IsFullTransitionArray()) {
+    DCHECK(number_of_transitions <= number_of_transitions_storage());
+    WRITE_FIELD(this, kTransitionLengthOffset,
+                Smi::FromInt(number_of_transitions));
+  }
+}
+
+
 #undef FIELD_ADDR
 #undef WRITE_FIELD
 #undef CONDITIONAL_WRITE_BARRIER