Initial work to remove the notion of all extension message payloads as strings.

chrome/browser/extensions/api/api_resource_event_notifier.cc

Index: chrome/browser/extensions/api/api_resource_event_notifier.cc
diff --git a/chrome/browser/extensions/api/api_resource_event_notifier.cc b/chrome/browser/extensions/api/api_resource_event_notifier.cc
index 6a15809c143c532ffabe941127e148f003f26a02..20a5e2007d7079a26716784d37093032d615cfa6 100644
--- a/chrome/browser/extensions/api/api_resource_event_notifier.cc
+++ b/chrome/browser/extensions/api/api_resource_event_notifier.cc
@@ -126,14 +126,11 @@ void APIResourceEventNotifier::DispatchEvent(const std::string &extension,
 
 void APIResourceEventNotifier::DispatchEventOnUIThread(
     const std::string &extension, DictionaryValue* event) {
-  ListValue args;
-
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
+  ListValue args;
   args.Set(0, event);
-  std::string json_args;
-  base::JSONWriter::Write(&args, &json_args);
-  router_->DispatchEventToExtension(src_extension_id_, extension, json_args,
+  router_->DispatchEventToExtension(src_extension_id_, extension, args,
                                     profile_, src_url_);
 }