Put display messages as 'additional' message.

Put display messages as 'additional' message.

Notification title has 2-line limit, therefore sometimes long
messages are cut off. The 'body' field has much more space for
longer text.

BUG=454827
R=oshima@chromium.org
TEST=manually

Committed: https://crrev.com/bf215fe52623ad5ab594153ca1182ffe4a4537d3
Cr-Commit-Position: refs/heads/master@{#326692}

[oshima, 2015-04-17 22:58:14]

lgtm

[Jun Mukai, 2015-04-17 23:04:15]

The CQ bit was checked by mukai@chromium.org

[commit-bot: I haz the power, 2015-04-17 23:06:47]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1094863006/1

[commit-bot: I haz the power, 2015-04-18 01:10:50]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-04-18 01:10:51]

Try jobs failed on following builders:
  linux_chromium_chromeos_ozone_rel_ng on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[Jun Mukai, 2015-04-23 23:00:49]

The CQ bit was checked by mukai@chromium.org

[Jun Mukai, 2015-04-23 23:00:50]

The patchset sent to the CQ was uploaded after l-g-t-m from oshima@chromium.org
Link to the patchset: https://codereview.chromium.org/1094863006/#ps20001
(title: "fix tests")

[commit-bot: I haz the power, 2015-04-23 23:01:26]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1094863006/20001

[commit-bot: I haz the power, 2015-04-23 23:40:03]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-04-23 23:40:55]

Patchset 2 (id:??) landed as
https://crrev.com/bf215fe52623ad5ab594153ca1182ffe4a4537d3
Cr-Commit-Position: refs/heads/master@{#326692}