Moves kb-key images from kb-key to it's child.

BUG=340364

Review URL: https://codereview.chromium.org/144733005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@249473 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 249473