add interceptors which do not mask existing properties

src/lookup.h

Index: src/lookup.h
diff --git a/src/lookup.h b/src/lookup.h
index a114bc5c0745d8fd42884dc9cd503244e119085d..a2e25c42470bb0c6d6fb9129c0a7cce755063040 100644
--- a/src/lookup.h
+++ b/src/lookup.h
@@ -46,13 +46,15 @@ class LookupIterator FINAL BASE_EMBEDDED {
                  Configuration configuration = PROTOTYPE_CHAIN)
       : configuration_(ComputeConfiguration(configuration, name)),
         state_(NOT_FOUND),
+        interceptor_state_(InterceptorState::kUninitialized),
         property_details_(NONE, v8::internal::DATA, 0),
         isolate_(name->GetIsolate()),
         name_(name),
         receiver_(receiver),
+        holder_(GetRoot(receiver_, isolate_)),
+        holder_map_(holder_->map(), isolate_),
+        initial_holder_(holder_),
         number_(DescriptorArray::kNotFound) {
-    holder_ = GetRoot();
-    holder_map_ = handle(holder_->map(), isolate_);
     Next();
   }
 
@@ -61,12 +63,14 @@ class LookupIterator FINAL BASE_EMBEDDED {
                  Configuration configuration = PROTOTYPE_CHAIN)
       : configuration_(ComputeConfiguration(configuration, name)),
         state_(NOT_FOUND),
+        interceptor_state_(InterceptorState::kUninitialized),
         property_details_(NONE, v8::internal::DATA, 0),
         isolate_(name->GetIsolate()),
         name_(name),
-        holder_map_(holder->map(), isolate_),
         receiver_(receiver),
         holder_(holder),
+        holder_map_(holder_->map(), isolate_),
+        initial_holder_(holder_),
         number_(DescriptorArray::kNotFound) {
     Next();
   }
@@ -95,7 +99,7 @@ class LookupIterator FINAL BASE_EMBEDDED {
     DCHECK(IsFound());
     return Handle<T>::cast(holder_);
   }
-  Handle<JSReceiver> GetRoot() const;
+  static Handle<JSReceiver> GetRoot(Handle<Object> receiver, Isolate* isolate);
   bool HolderIsReceiverOrHiddenPrototype() const;
 
   /* ACCESS_CHECK */
@@ -148,12 +152,21 @@ class LookupIterator FINAL BASE_EMBEDDED {
   void InternalizeName();
 
  private:
+  enum class InterceptorState {
+    kUninitialized,
+    kSkipNonMasking,
+    kProcessNonMasking
+  };
+
   Handle<Map> GetReceiverMap() const;
 
   MUST_USE_RESULT inline JSReceiver* NextHolder(Map* map);
   inline State LookupInHolder(Map* map, JSReceiver* holder);
+  void RestartLookupForNonMaskingInterceptors();
+  State LookupNonMaskingInterceptorInHolder(Map* map, JSReceiver* holder);
   Handle<Object> FetchValue() const;
   void ReloadPropertyInformation();
+  bool SkipInterceptor(JSObject* holder);
 
   bool IsBootstrapping() const;
 
@@ -187,17 +200,18 @@ class LookupIterator FINAL BASE_EMBEDDED {
 
   // If configuration_ becomes mutable, update
   // HolderIsReceiverOrHiddenPrototype.
-  Configuration configuration_;
+  const Configuration configuration_;
   State state_;
   bool has_property_;
+  InterceptorState interceptor_state_;
   PropertyDetails property_details_;
-  Isolate* isolate_;
+  Isolate* const isolate_;
   Handle<Name> name_;
-  Handle<Map> holder_map_;
   Handle<Object> transition_;
-  Handle<Object> receiver_;
+  const Handle<Object> receiver_;
   Handle<JSReceiver> holder_;
-
+  Handle<Map> holder_map_;
+  const Handle<JSReceiver> initial_holder_;
   int number_;
 };