Implement immutable prototype chains

include/v8.h

Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index 8b8507f5520ff2fcf9ba8dbdbe21def44ead8dfa..ff265c44828a2c5e6ec7b8c601284dc788177231 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -4827,6 +4827,17 @@ class V8_EXPORT ObjectTemplate : public Template {
    */
   void SetInternalFieldCount(int value);
 
+  /**
+   * Returns true if the object will be an immutable prototype exotic object.
+   */
+  bool ImmutableProto();
+
+  /**
+   * Makes the ObjectTempate for an immutable prototype exotic object, with an
+   * immutable __proto__.
+   */
+  void SetImmutableProto();
+
  private:
   ObjectTemplate();
   static Local<ObjectTemplate> New(internal::Isolate* isolate,