Hanldify JSObject::PreventExtensions method.

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index 047c8d822f82847bba437d0ef88a124b97afd5e6..1926eda2776c2bd73182befd9dac4ed553630730 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -1825,10 +1825,12 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_GetOwnProperty) {
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_PreventExtensions) {
-  SealHandleScope shs(isolate);
+  HandleScope scope(isolate);
   ASSERT(args.length() == 1);
-  CONVERT_ARG_CHECKED(JSObject, obj, 0);
-  return obj->PreventExtensions();
+  CONVERT_ARG_HANDLE_CHECKED(JSObject, obj, 0);
+  Handle<Object> result = JSObject::PreventExtensions(obj);
+  RETURN_IF_EMPTY_HANDLE(isolate, result);
+  return *result;
 }
 
 
@@ -1852,8 +1854,7 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_RegExpCompile) {
   CONVERT_ARG_HANDLE_CHECKED(JSRegExp, re, 0);
   CONVERT_ARG_HANDLE_CHECKED(String, pattern, 1);
   CONVERT_ARG_HANDLE_CHECKED(String, flags, 2);
-  Handle<Object> result =
-      RegExpImpl::Compile(re, pattern, flags);
+  Handle<Object> result = RegExpImpl::Compile(re, pattern, flags);
   RETURN_IF_EMPTY_HANDLE(isolate, result);
   return *result;
 }