Bug 830000 - Add CallArgs::handleAt; r=Waldo

js/src/jsapi.h

@@ -628,6 +628,16 @@ class CallArgs : public CallReceiver
     friend CallArgs CallArgsFromArgv(unsigned, Value *);
     friend CallArgs CallArgsFromSp(unsigned, Value *);
     Value &operator[](unsigned i) const { JS_ASSERT(i < argc_); return argv_[i]; }
+    MutableHandleValue handleAt(unsigned i)
+    {
+        JS_ASSERT(i < argc_);
+        return MutableHandleValue::fromMarkedLocation(&argv_[i]);
+    }
+    HandleValue handleAt(unsigned i) const
+    {
+        JS_ASSERT(i < argc_);
+        return HandleValue::fromMarkedLocation(&argv_[i]);
+    }
     Value get(unsigned i) const
     {
         return i < length() ? argv_[i] : UndefinedValue();