Revert of Fix DEATH_BY_SIGNAL test helper (https://codereview.chromium.org/193453002/)

Reason for revert:
UnitTests.DeathBySignal is failing on Android: http://crbug.com/352226

Original issue's description:
> Fix DEATH_BY_SIGNAL test helper
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=256653

TBR=jln@chromium.org,mdempsky@google.com
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/198923004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256872 0039d316-1c4b-4281-b951-d872f2087c98
Define the DISABLE_CAPS_LOCK and TOGGLE_CAPS_LOCK accelerators for OS_CHROMEOS only.

These accelerators also fire on Windows ASH while processing the Shift key causing a DCHECK.

BUG=351976
R=sadrul@chromium.org, sky@chromium.org, sadrul

Review URL: https://codereview.chromium.org/198063004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256873 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 256873