Increase coverage of telemetry's user_agent_unittest

Increase coverage of telemetry's user_agent_unittest

Added a mobile and desktop testing in case the browser being tested has a
user agent that defaults to the tablet user agent.

BUG=421229
Committed: https://crrev.com/63f233bcd3a8a6d7f3cfb5183b62160c96ded98e
Cr-Commit-Position: refs/heads/master@{#300349}

[Daniel Imms, 2014-10-07 22:41:48]

daniimms@amazon.com changed reviewers:
+ tonyg@chromium.org

[tonyg, 2014-10-14 21:13:43]

The CQ bit was checked by tonyg@chromium.org

[tonyg, 2014-10-14 21:13:44]

lgtm

[commit-bot: I haz the power, 2014-10-14 21:14:16]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/640453002/1

[commit-bot: I haz the power, 2014-10-14 21:25:36]

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

[commit-bot: I haz the power, 2014-10-14 21:25:37]

Try jobs failed on following builders:
  chromium_presubmit on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/chromium_presub...)

[tonyg, 2014-10-14 21:30:58]

daniimms@amazon.com is not in AUTHORS file. If you are a new contributor, please
visit
http://www.chromium.org/developers/contributing-code and read the "Legal"
section
If you are a chromite, verify the contributor signed the CLA.

[Daniel Imms, 2014-10-14 21:50:33]

On 2014/10/14 21:30:58, tonyg wrote:
> mailto:daniimms@amazon.com is not in AUTHORS file. If you are a new
contributor, please
> visit
> http://www.chromium.org/developers/contributing-code and read the "Legal"
> section
> If you are a chromite, verify the contributor signed the CLA.

Hey Tony, I should be in the CCLA and this is my first commit so I'll need to be
added to the AUTHORS file.

[Daniel Imms, 2014-10-14 22:19:27]

On 2014/10/14 21:50:33, Daniel imms wrote:
> On 2014/10/14 21:30:58, tonyg wrote:
> > mailto:daniimms@amazon.com is not in AUTHORS file. If you are a new
> contributor, please
> > visit
> > http://www.chromium.org/developers/contributing-code and read the "Legal"
> > section
> > If you are a chromite, verify the contributor signed the CLA.
> 
> Hey Tony, I should be in the CCLA and this is my first commit so I'll need to
be
> added to the AUTHORS file.

Added myself to AUTHORS file

[tonyg, 2014-10-20 20:23:22]

The CQ bit was checked by tonyg@chromium.org

[tonyg, 2014-10-20 20:23:22]

lgtm

[commit-bot: I haz the power, 2014-10-20 20:24:40]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/640453002/20001

[commit-bot: I haz the power, 2014-10-20 22:08:53]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2014-10-20 22:10:36]

Patchset 2 (id:??) landed as
https://crrev.com/63f233bcd3a8a6d7f3cfb5183b62160c96ded98e
Cr-Commit-Position: refs/heads/master@{#300349}