Like here: http://www.igvita.com/posa/high-performance-networking-in-google-chrome/#dns-prefetching
Created attachment 186450 [details]
Please don't submit the patch as-is and just review the concept. I'll add an api to QHostInfo specifically for this since you get a warning otherwise.
The change to Qt to make this patch work without warnings is now up for review at https://codereview.qt-project.org/#change,46776
Comment on attachment 186450 [details]
Attachment 186450 [details] did not pass win-ews (win):
This is already implemented in Chrome::mouseDidMoveOverElement(). Is this version in client code different?
I think Alexey is right. The existing code issues the prefetch request through the correct layer, which in the current design for the Qt port will result in a DNS lookup in the web process, which is also where we currently do networking. This patch on the other hand will issue a DNS request in the ui process, populating the in-process QHostInfoCache in the wrong process.