Keep prototype maps in dictionary mode until ICs see them

src/lookup.cc

 // Copyright 2014 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 "src/lookup.h"
 
 #include "src/bootstrapper.h"
 #include "src/deoptimizer.h"
 #include "src/elements.h"
 #include "src/field-type.h"
@@ skipping 478 matching lines @@
   // Optimization that only works if configuration_ is not mutable.
   if (!check_prototype_chain()) return true;
   DisallowHeapAllocation no_gc;
   if (*receiver_ == *holder_) return true;
   if (!receiver_->IsJSReceiver()) return false;
   JSReceiver* current = JSReceiver::cast(*receiver_);
   JSReceiver* object = *holder_;
   if (!current->map()->has_hidden_prototype()) return false;
   // JSProxy do not occur as hidden prototypes.
   if (object->IsJSProxy()) return false;
-  PrototypeIterator iter(isolate(), current,
-                         PrototypeIterator::START_AT_PROTOTYPE,
+  PrototypeIterator iter(isolate(), current, kStartAtPrototype,
                          PrototypeIterator::END_AT_NON_HIDDEN);
   while (!iter.IsAtEnd()) {
     if (iter.GetCurrent<JSReceiver>() == object) return true;
     iter.Advance();
   }
   return false;
 }
 
 
 Handle<Object> LookupIterator::FetchValue() const {
@@ skipping 242 matching lines @@
     case v8::internal::kAccessor:
       return ACCESSOR;
   }
 
   UNREACHABLE();
   return state_;
 }
 
 }  // namespace internal
 }  // namespace v8