Add 10dp between app search result options.

R=xiyuan@chromium.org
BUG=312459

Review URL: https://codereview.chromium.org/69293011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@234662 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 234662