Non-printable characters will are printed as escapes.
NUL won't terminate error message prematurely now.

Change-Id: Ie24b34e377221e9b99d2268f8dfb5ce26d064cc2
Reviewed-on: https://chromium-review.googlesource.com/509490Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Wiktor Garbacz <wiktorg@google.com>
Cr-Commit-Position: refs/heads/master@{#45586}