[OriginChip, OSX] Hide on focus is switchable

Only hide the origin chip for an "OnSetFocus" event if the flag for
hide-on-mouse-release is set. (hide-on-user-input is controlled by the
OmniboxEditModel, so no additional work needed for that).

BUG=338563

Review URL: https://codereview.chromium.org/181383017

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@254603 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 254603