[Extensions] Update last_error.js, send_request.js

extensions/renderer/resources/send_request.js

Index: extensions/renderer/resources/send_request.js
diff --git a/extensions/renderer/resources/send_request.js b/extensions/renderer/resources/send_request.js
index 9fed10e7f4279bd936b0f52d982a3460b038daa4..d9de317a692c0641592ac39014cb30d4938365a8 100644
--- a/extensions/renderer/resources/send_request.js
+++ b/extensions/renderer/resources/send_request.js
@@ -9,7 +9,7 @@ var natives = requireNative('sendRequest');
 var validate = require('schemaUtils').validate;
 
 // All outstanding requests from sendRequest().
-var requests = {};
+var requests = { __proto__: null };
 
 // Used to prevent double Activity Logging for API calls that use both custom
 // bindings and ExtensionFunctions (via sendRequest).
@@ -88,7 +88,7 @@ function handleResponse(requestId, name, success, responseList, error) {
 }
 
 function prepareRequest(args, argSchemas) {
-  var request = {};
+  var request = { __proto__: null };
   var argCount = args.length;
 
   // Look for callback param.
@@ -99,11 +99,7 @@ function prepareRequest(args, argSchemas) {
     --argCount;
   }
 
-  request.args = [];
-  for (var k = 0; k < argCount; k++) {
-    request.args[k] = args[k];
-  }
-
+  request.args = $Array.slice(args, 0, argCount);
   return request;
 }
 
@@ -119,7 +115,7 @@ function prepareRequest(args, argSchemas) {
 function sendRequest(functionName, args, argSchemas, optArgs) {
   calledSendRequest = true;
   if (!optArgs)
-    optArgs = {};
+    optArgs = { __proto__: null };

[robwu, 2016/04/23 09:54:38]

Can you also check the callers of sendRequest and make sure that optArgs
inherits from null?

E.g. the properties of optArgs in binding.js will leak when you "optArgs.stack"
is accessed below.

[Devlin, 2016/04/25 21:50:35]

That wasn't as painful as I thought it'd be, given how many callers of
sendRequest() there are.  Done.

   var request = prepareRequest(args, argSchemas);
   request.stack = optArgs.stack || exceptionHandler.getExtensionStackTrace();
   if (optArgs.customCallback) {