Update to V8 with partial snapshots. This is taken from the partial_snapshot branch of V8.
diff --git a/src/messages.js b/src/messages.js
index df008c9..7c939ca 100644
--- a/src/messages.js
+++ b/src/messages.js
@@ -27,6 +27,16 @@
 
 
 // -------------------------------------------------------------------
+//
+// Matches Script::Type from objects.h
+var TYPE_NATIVE = 0;
+var TYPE_EXTENSION = 1;
+var TYPE_NORMAL = 2;
+
+// Matches Script::CompilationType from objects.h
+var COMPILATION_TYPE_HOST = 0;
+var COMPILATION_TYPE_EVAL = 1;
+var COMPILATION_TYPE_JSON = 2;
 
 // Lazily initialized.
 var kVowelSounds = 0;
@@ -162,6 +172,8 @@
       value_and_accessor:           "Invalid property.  A property cannot both have accessors and be writable or have a value: %0",
       proto_object_or_null:         "Object prototype may only be an Object or null",
       property_desc_object:         "Property description must be an object: %0",
+      redefine_disallowed:          "Cannot redefine property: %0",
+      define_disallowed:            "Cannot define property, object is not extensible: %0",
       // RangeError
       invalid_array_length:         "Invalid array length",
       stack_overflow:               "Maximum call stack size exceeded",
@@ -630,7 +642,7 @@
 
 CallSite.prototype.isEval = function () {
   var script = %FunctionGetScript(this.fun);
-  return script && script.compilation_type == 1;
+  return script && script.compilation_type == COMPILATION_TYPE_EVAL;
 };
 
 CallSite.prototype.getEvalOrigin = function () {
@@ -652,7 +664,7 @@
   }
   // Maybe this is an evaluation?
   var script = %FunctionGetScript(this.fun);
-  if (script && script.compilation_type == 1)
+  if (script && script.compilation_type == COMPILATION_TYPE_EVAL)
     return "eval";
   return null;
 };
@@ -708,7 +720,7 @@
 
 CallSite.prototype.isNative = function () {
   var script = %FunctionGetScript(this.fun);
-  return script ? (script.type == 0) : false;
+  return script ? (script.type == TYPE_NATIVE) : false;
 };
 
 CallSite.prototype.getPosition = function () {
@@ -732,7 +744,7 @@
   
   var eval_from_script = script.eval_from_script;
   if (eval_from_script) {
-    if (eval_from_script.compilation_type == 1) {
+    if (eval_from_script.compilation_type == COMPILATION_TYPE_EVAL) {
       // eval script originated from another eval.
       eval_origin += " (eval at " + FormatEvalOrigin(eval_from_script) + ")";
     } else {