Remove the no-longer-used chromeos::switches::kHasChromeOSKeyboard

Remove the no-longer-used chromeos::switches::kHasChromeOSKeyboard

The last usage of this switch was removed in this CL:
https://codereview.chromium.org/1188693002/. We don't need to keep it
around.

BUG=501121
Committed: https://crrev.com/3920b7273eca34d1108b048f1eec3fd573b86524
Cr-Commit-Position: refs/heads/master@{#341364}

[afakhry, 2015-07-31 01:08:03]

afakhry@chromium.org changed reviewers:
+ derat@chromium.org

[afakhry, 2015-07-31 01:08:03]

derat@chromium.org: Could you please review this CL? Thanks!

[use derat at chromium.org, 2015-07-31 03:50:50]

derat@google.com changed reviewers:
+ derat@google.com

[use derat at chromium.org, 2015-07-31 03:50:51]

lgtm

[afakhry, 2015-07-31 17:21:02]

On 2015/07/31 03:50:51, use derat at chromium.org wrote:
> lgtm

I think you need to give the lgtm using your @chromium.org account. This still
lacks OWNERS lgtm. :)

[Daniel Erat, 2015-07-31 17:49:41]

lgtm

ugh, sorry; i wish that chromium.org accounts didn't exist. i've given up
multilogin ever working properly on google code, sites, etc. and basically just
use an incognito window whenever i notice that it's switched back to my
google.com account incorrectly. must've missed that here.

[afakhry, 2015-07-31 17:55:15]

The CQ bit was checked by afakhry@chromium.org

[commit-bot: I haz the power, 2015-07-31 17:55:57]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1269793005/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1269793005/1

[commit-bot: I haz the power, 2015-07-31 18:01:05]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-07-31 18:01:41]

Patchset 1 (id:??) landed as
https://crrev.com/3920b7273eca34d1108b048f1eec3fd573b86524
Cr-Commit-Position: refs/heads/master@{#341364}