Fix crash on NULL pointer when the browser is compiled with use_cups=0

Please see https://bugs.gentoo.org/show_bug.cgi?id=530682 for context.

The idea is to make cups dependency optional at compile time. Even without
cups one can print to file (pdf) or use cloud print.

BUG=none
R=thestig@chromium.org

Review URL: https://codereview.chromium.org/862023002

Cr-Commit-Position: refs/heads/master@{#312594}
2 files changed