Removes the options for voice search in the app-list only.

We use the same checkbox for the hotword.search_enabled for the
voice search, so this checkbox is just unnecessary.

I'll create another CL to cleanup the hotword.app_list_enabled
preference item, but this is intentionally small to be merged
easily.

BUG=345856
R=rlp@chromium.org, estade@chromium.org
TEST=manually

Review URL: https://codereview.chromium.org/167733004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253301 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 253301
Move PowerMonitor to Application Context

BUG=341231

Review URL: https://codereview.chromium.org/167243005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253302 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 253302