Remove "keyboard" from keyboard strings.

BUG=344555
TEST=manual
NOTRY=true

Review URL: https://codereview.chromium.org/175513004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256871 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 256871