Should cops be able to go through an arrested person's phone?

In California a law may be passed to keep police officers from going through anyone's phone that they arrest. They will have to obtain a warrent to look through the phone. I think this is a good law because what is in my phone is none of an officer's business. If they can get a warrent to search my phone then I prolly have things on there i shouldn't anyway so then I would deserve it.