Add warning icon to media throttle info bar to make it consistent with others

Add warning icon to media throttle info bar to make it consistent with others

As suggested in the crbug.

BUG=532745
Committed: https://crrev.com/bd8f5de058d1d59c780df4663fd86a9b7ab3ab00
Cr-Commit-Position: refs/heads/master@{#353179}

[qinmin, 2015-10-07 22:53:36]

qinmin@chromium.org changed reviewers:
+ dtrainor@chromium.org

[qinmin, 2015-10-07 22:53:37]

PTAL

[David Trainor- moved to gerrit, 2015-10-08 20:38:06]

lgtm

[qinmin, 2015-10-08 21:12:20]

The CQ bit was checked by qinmin@chromium.org

[commit-bot: I haz the power, 2015-10-08 21:13:15]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1392913003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1392913003/1

[commit-bot: I haz the power, 2015-10-08 21:56:56]

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

[commit-bot: I haz the power, 2015-10-08 21:56:56]

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

[qinmin, 2015-10-08 23:50:45]

The CQ bit was checked by qinmin@chromium.org

[qinmin, 2015-10-08 23:50:46]

The patchset sent to the CQ was uploaded after l-g-t-m from
dtrainor@chromium.org
Link to the patchset: https://codereview.chromium.org/1392913003/#ps20001
(title: " ")

[commit-bot: I haz the power, 2015-10-08 23:52:17]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1392913003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1392913003/20001

[commit-bot: I haz the power, 2015-10-09 00:14:17]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-10-09 00:15:08]

Patchset 2 (id:??) landed as
https://crrev.com/bd8f5de058d1d59c780df4663fd86a9b7ab3ab00
Cr-Commit-Position: refs/heads/master@{#353179}