My iphone 6 screen is frozen?

I was just scrolling through google (the app not through safari). Just reading my daily dose of news. As I scrolled the screen froze. About 30 minutes later, the screen turned into the screen when you usually turn on the phone it appears or when you have an update (the white background with the black apple).

So far the screen has been stuck like that for 4 hours now.
I've been pressing and holding to buttons to try and get it to work but it doesn't.

Maybe try plugging to a laptop and restarting it through there. Or if you have to restore the phone completely through a laptop. Hope this helps.

I did it without restarting it. Since it was already on the white background screen it meant that it was already rebooting itself. Don't understand how it took a few hours to do so…