Support symbol-named properties in API

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 9d96b503386c840222139aeee9cca23751cc4b2f..e3da80328d79463dc0ef3a67637244cf1ffe2f6d 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -10829,6 +10829,10 @@ class InterceptorInfo: public Struct {
   DECL_ACCESSORS(deleter, Object)
   DECL_ACCESSORS(enumerator, Object)
   DECL_ACCESSORS(data, Object)
+  DECL_BOOLEAN_ACCESSORS(can_intercept_symbols)
+
+  inline int flags();
+  inline void set_flags(int flags);
 
   static inline InterceptorInfo* cast(Object* obj);
 
@@ -10842,7 +10846,10 @@ class InterceptorInfo: public Struct {
   static const int kDeleterOffset = kQueryOffset + kPointerSize;
   static const int kEnumeratorOffset = kDeleterOffset + kPointerSize;
   static const int kDataOffset = kEnumeratorOffset + kPointerSize;
-  static const int kSize = kDataOffset + kPointerSize;
+  static const int kFlagsOffset = kDataOffset + kPointerSize;
+  static const int kSize = kFlagsOffset + kPointerSize;
+
+  static const int kCanInterceptSymbolsBit = 0;
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(InterceptorInfo);