Remove ListValue::Append(new {Fundamental,String}Value(...)) pattern in //net

net/proxy/proxy_service.cc

Index: net/proxy/proxy_service.cc
diff --git a/net/proxy/proxy_service.cc b/net/proxy/proxy_service.cc
index 403b52cc2756fd64c9596ed16d0e0f379fb29b92..295bad2780281904c862d23ea2f34337da101f85 100644
--- a/net/proxy/proxy_service.cc
+++ b/net/proxy/proxy_service.cc
@@ -318,7 +318,7 @@ std::unique_ptr<base::Value> NetLogBadProxyListCallback(
 
   for (ProxyRetryInfoMap::const_iterator iter = retry_info->begin();
        iter != retry_info->end(); ++iter) {
-    list->Append(new base::StringValue(iter->first));
+    list->AppendString(iter->first);
   }
   dict->Set("bad_proxy_list", list);
   return std::move(dict);