[stubs] Introduce NonPrimitiveToPrimitive builtin.

src/factory.h

 // 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.
 
 #ifndef V8_FACTORY_H_
 #define V8_FACTORY_H_
 
 #include "src/isolate.h"
 #include "src/messages.h"
 #include "src/type-feedback-vector.h"
@@ skipping 666 matching lines @@
                              int capture_count);
 
   // Returns the value for a known global constant (a property of the global
   // object which is neither configurable nor writable) like 'undefined'.
   // Returns a null handle when the given name is unknown.
   Handle<Object> GlobalConstantFor(Handle<Name> name);
 
   // Converts the given boolean condition to JavaScript boolean value.
   Handle<Object> ToBoolean(bool value);
 
+  // Converts the given ToPrimitive hint to it's string representation.
+  Handle<String> ToPrimitiveHintString(ToPrimitiveHint hint);
+
  private:
   Isolate* isolate() { return reinterpret_cast<Isolate*>(this); }
 
   // Creates a heap object based on the map. The fields of the heap object are
   // not initialized by New<>() functions. It's the responsibility of the caller
   // to do that.
   template<typename T>
   Handle<T> New(Handle<Map> map, AllocationSpace space);
 
   template<typename T>
@@ skipping 16 matching lines @@
 
   // Create a JSArray with no elements and no length.
   Handle<JSArray> NewJSArray(ElementsKind elements_kind,
                              PretenureFlag pretenure = NOT_TENURED);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_FACTORY_H_