Sandbox html_viewer on Linux.

Reland "Sandbox html_viewer on Linux."

This fixes a midair collision with a file move.

This creates a font_service which does the same role as
font_config_ipc_linux.cc does in content/. This lets us sandbox the
html_viewer, while still being able to communicate with fontconfig.

Also prewarms the ICU timezone data, along with doing all the
prewarming that's done in the core_services sandbox.

BUG=492524
NOPRESUBMIT=true
First Review URL: https://codereview.chromium.org/1274743004

Committed: https://crrev.com/7eb0efde374571b5c76417c7df061fee4cd7acd8
Cr-Commit-Position: refs/heads/master@{#342409}

[Elliot Glaysher, 2015-08-07 17:35:47]

erg@chromium.org changed reviewers:
+ jam@chromium.org

[Elliot Glaysher, 2015-08-07 17:36:07]

Rubber stampable. The only differences are in Patch Set 2.

[jam, 2015-08-07 19:22:43]

lgtm

[Elliot Glaysher, 2015-08-07 19:23:00]

The CQ bit was checked by erg@chromium.org

[commit-bot: I haz the power, 2015-08-07 19:23:19]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1280043003/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1280043003/40001

[commit-bot: I haz the power, 2015-08-07 19:27:05]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-08-07 19:27:31]

Patchset 3 (id:??) landed as
https://crrev.com/7eb0efde374571b5c76417c7df061fee4cd7acd8
Cr-Commit-Position: refs/heads/master@{#342409}