Add support for per-isolate private symbols

src/symbol.js

Index: src/symbol.js
diff --git a/src/symbol.js b/src/symbol.js
index 49f909694c19f3ee44c60a39def7fbbd0f39c6a5..aec80551f438e85b384e5ca56303d0d7a7392017 100644
--- a/src/symbol.js
+++ b/src/symbol.js
@@ -63,30 +63,17 @@ function SymbolValueOf() {
 }
 
 
-function GetSymbolRegistry() {
-  var registry = %SymbolRegistry();
-  if (!('internal' in registry)) {
-    registry.internal = {__proto__: null};
-    registry.for = {__proto__: null};
-    registry.keyFor = {__proto__: null};
-  }
-  return registry;
-}
-
-
 function InternalSymbol(key) {
-  var registry = GetSymbolRegistry();
-  if (!(key in registry.internal)) {
-    registry.internal[key] = %CreateSymbol(key);
-  }
-  return registry.internal[key];
+  var registry = %SymbolRegistry().for_intern;

[Michael Starzinger, 2014/03/24 15:17:19]

nit: The usage of the local variable "registry" is different here and below,
this is a little bit confusing IMHO.

[rossberg, 2014/03/24 15:54:46]

Done.

+  if (IS_UNDEFINED(registry[key])) registry[key] = %CreateSymbol(key);
+  return registry[key];
 }
 
 
 function SymbolFor(key) {
   key = TO_STRING_INLINE(key);
-  var registry = GetSymbolRegistry();
-  if (!(key in registry.for)) {
+  var registry = %SymbolRegistry();
+  if (IS_UNDEFINED(registry.for[key])) {
     var symbol = %CreateSymbol(key);
     registry.for[key] = symbol;
     registry.keyFor[symbol] = key;
@@ -96,10 +83,8 @@ function SymbolFor(key) {
 
 
 function SymbolKeyFor(symbol) {
-  if (!IS_SYMBOL(symbol)) {
-    throw MakeTypeError("not_a_symbol", [symbol]);
-  }
-  return GetSymbolRegistry().keyFor[symbol];
+  if (!IS_SYMBOL(symbol)) throw MakeTypeError("not_a_symbol", [symbol]);
+  return %SymbolRegistry().keyFor[symbol];
 }