[ic] Don't check full prototype chain if name is a private symbol.

src/prototype.h

Index: src/prototype.h
diff --git a/src/prototype.h b/src/prototype.h
index 6e9015da63f1d8029592c9632d2b02ae45cc5bc3..d052510b497480292e4c837977c514db89cd6089 100644
--- a/src/prototype.h
+++ b/src/prototype.h
@@ -53,21 +53,35 @@ class PrototypeIterator {
     if (where_to_start == kStartAtPrototype) Advance();
   }
 
-  explicit PrototypeIterator(Map* receiver_map)
+  explicit PrototypeIterator(Map* receiver_map,
+                             WhereToEnd where_to_end = END_AT_NULL)
       : isolate_(receiver_map->GetIsolate()),
         object_(receiver_map->GetPrototypeChainRootMap(isolate_)->prototype()),
-        where_to_end_(END_AT_NULL),
+        where_to_end_(where_to_end),
         is_at_end_(object_->IsNull(isolate_)),
-        seen_proxies_(0) {}
+        seen_proxies_(0) {
+    if (!is_at_end_ && where_to_end_ == END_AT_NON_HIDDEN) {
+      DCHECK(object_->IsJSReceiver());
+      Map* map = JSReceiver::cast(object_)->map();
+      is_at_end_ = !map->has_hidden_prototype();
+    }
+  }
 
-  explicit PrototypeIterator(Handle<Map> receiver_map)
+  explicit PrototypeIterator(Handle<Map> receiver_map,
+                             WhereToEnd where_to_end = END_AT_NULL)
       : isolate_(receiver_map->GetIsolate()),
         object_(NULL),
         handle_(receiver_map->GetPrototypeChainRootMap(isolate_)->prototype(),
                 isolate_),
-        where_to_end_(END_AT_NULL),
+        where_to_end_(where_to_end),
         is_at_end_(handle_->IsNull(isolate_)),
-        seen_proxies_(0) {}
+        seen_proxies_(0) {
+    if (!is_at_end_ && where_to_end_ == END_AT_NON_HIDDEN) {
+      DCHECK(handle_->IsJSReceiver());
+      Map* map = JSReceiver::cast(*handle_)->map();
+      is_at_end_ = !map->has_hidden_prototype();
+    }
+  }
 
   ~PrototypeIterator() {}