v8::Private::ForApi should be context-independent.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 5327b7a7fc69301413bae1b8d8c39166a4a4c250..50c07a6166d65e910509ded38c357ade86e87919 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -9656,6 +9656,10 @@ class Symbol: public Name {
   // a load.
   DECL_BOOLEAN_ACCESSORS(is_well_known_symbol)
 
+  // [is_public]: Whether this is a symbol created by Symbol.for. Calling
+  // Symbol.keyFor on such a symbol simply needs to return the attached name.
+  DECL_BOOLEAN_ACCESSORS(is_public)
+
   DECLARE_CAST(Symbol)
 
   // Dispatched behavior.
@@ -9670,6 +9674,7 @@ class Symbol: public Name {
   // Flags layout.
   static const int kPrivateBit = 0;
   static const int kWellKnownSymbolBit = 1;
+  static const int kIsPublicBit = 2;

[peria, 2016/12/06 05:12:36]

inconsistent with "kPrivateBit"

[Yang, 2016/12/06 12:53:07]

Done.

 
   typedef FixedBodyDescriptor<kNameOffset, kFlagsOffset, kSize> BodyDescriptor;