Linux: Depend on liberation-fonts package. (try 2)

Linux: Depend on liberation-fonts package. (try 2)

Without these fonts, text in the built-in PDF viewer may not display
correctly.

Unfortunately we can only do this for the .deb packages at the moment.
There's no common liberation-fonts package for RPMs. See
https://crbug.com/519322.

BUG=369991
Committed: https://crrev.com/d98c44a7c597056bcb14b7ff1e73dc5e2589482f
Cr-Commit-Position: refs/heads/master@{#342854}

[Lei Zhang, 2015-08-11 18:36:00]

thestig@chromium.org changed reviewers:
+ mmoss@chromium.org

[Michael Moss, 2015-08-11 18:42:14]

lgtm

[Lei Zhang, 2015-08-11 18:44:27]

The CQ bit was checked by thestig@chromium.org

[commit-bot: I haz the power, 2015-08-11 18:45:27]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1274043004/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1274043004/20001

[commit-bot: I haz the power, 2015-08-11 18:50:18]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-08-11 18:50:57]

Patchset 2 (id:??) landed as
https://crrev.com/d98c44a7c597056bcb14b7ff1e73dc5e2589482f
Cr-Commit-Position: refs/heads/master@{#342854}