These were removed from the base class (ChromeContentBrowserClient) and
we do not need them any more due to #3130.

Chromium change:

https://chromium.googlesource.com/chromium/src/+/e7db7a21873d31f5c74a81670a3047c08757d8ed

commit e7db7a21873d31f5c74a81670a3047c08757d8ed
Author: Maks Orlovich <morlovich@chromium.org>
Date:   Thu Jul 25 01:47:46 2019 +0000

    Android MediaResourceGetterImpl: use RestrictedCookieManager for policy-following cookie access.

    This removes the last use of ContentBrowserClient::AllowGetCookie, and permits the removal
    of AllowGetCookie/AllowSetCookie which is also done in this CL.

    Bug: 965982