Reland "Limit the number of transitions allowed per hidden class."

src/transitions-inl.h

 // Copyright 2012 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.
 
 #ifndef V8_TRANSITIONS_INL_H_
 #define V8_TRANSITIONS_INL_H_
 
 #include "src/transitions.h"
 
 namespace v8 {
@@ skipping 142 matching lines @@
 void TransitionArray::NoIncrementalWriteBarrierSet(int transition_number,
                                                    Name* key,
                                                    Map* target) {
   FixedArray::NoIncrementalWriteBarrierSet(
       this, ToKeyIndex(transition_number), key);
   FixedArray::NoIncrementalWriteBarrierSet(
       this, ToTargetIndex(transition_number), target);
 }
 
 
+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
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TRANSITIONS_INL_H_