chromeos: Simplify chromeos::input_method::XKeyboard interface.

Notable changes:
 * Replace the num-lock related methods with a single DisableNumLock(), since
   num-lock LED is always turned off in chromeos (more details at
   crbug.com/124189)
 * Remove SetLockedModifiers(), since DisableNumLock() and SetCapsLockEnabled()
   are sufficient.
 * Remove GetLockedModifiers(), since only CapsLockIsEnabled() is useful.

BUG=none
R=derat@chromium.org, yukishiino@chromium.org

Review URL: https://codereview.chromium.org/189663009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255943 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 255943
Eliminate BrowserThread dependency from WebDataAutofillServiceTest.

This CL replaces the usage of content::BrowserThread by base::Thread in a
straightforward fashion. It also removes now-unneeded includes and DEPS
temporary allowances relating to core Autofill test code.

BUG=303083
R=joi@chromium.org

Review URL: https://codereview.chromium.org/190213003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255944 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 255944