Add CallSiteGetFunctionArguments to frame object

v8.diff

diff --git a/src/messages.js b/src/messages.js
index c86c12d..ad5921c 100644
--- a/src/messages.js
+++ b/src/messages.js
@@ -801,6 +801,10 @@ function CallSiteGetFunction() {
       ? UNDEFINED : GET_PRIVATE(this, CallSiteFunctionKey);
 }

+function CallSiteGetFunctionArguments() {
+    return GET_PRIVATE(this, CallSiteFunctionKey).arguments;
+}
+
 function CallSiteGetFunctionName() {
   // See if the function knows its own name
   var name = GET_PRIVATE(this, CallSiteFunctionKey).name;
@@ -973,6 +977,7 @@ SetUpLockedPrototype(CallSite, $Array("receiver", "fun", "pos"), $Array(
   "getEvalOrigin", CallSiteGetEvalOrigin,
   "getScriptNameOrSourceURL", CallSiteGetScriptNameOrSourceURL,
   "getFunction", CallSiteGetFunction,
+  "getFunctionArguments", CallSiteGetFunctionArguments,
   "getFunctionName", CallSiteGetFunctionName,
   "getMethodName", CallSiteGetMethodName,
   "getFileName", CallSiteGetFileName,