Revert of Migrate Object.prototype.valueOf to CSA

src/js/v8natives.js

Index: src/js/v8natives.js
diff --git a/src/js/v8natives.js b/src/js/v8natives.js
index 79a2fb761ed5ff57aaa3d7ee4a54e3b8c1de6c6d..29f9c45efa854360c259e620da1209d0a511e372 100644
--- a/src/js/v8natives.js
+++ b/src/js/v8natives.js
@@ -28,6 +28,12 @@
 function ObjectToLocaleString() {
   CHECK_OBJECT_COERCIBLE(this, "Object.prototype.toLocaleString");
   return this.toString();
+}
+
+
+// ES6 19.1.3.7 Object.prototype.valueOf()
+function ObjectValueOf() {
+  return TO_OBJECT(this);
 }
 
 
@@ -70,7 +76,7 @@
 utils.InstallFunctions(GlobalObject.prototype, DONT_ENUM, [
   "toString", ObjectToString,
   "toLocaleString", ObjectToLocaleString,
-  // valueOf is added in bootstrapper.cc.
+  "valueOf", ObjectValueOf,
   "isPrototypeOf", ObjectIsPrototypeOf,
   // propertyIsEnumerable is added in bootstrapper.cc.
   // __defineGetter__ is added in bootstrapper.cc.
@@ -107,4 +113,8 @@
   to.ObjectHasOwnProperty = GlobalObject.prototype.hasOwnProperty;
 });
 
+%InstallToContext([
+  "object_value_of", ObjectValueOf,
+]);
+
 })