Hides auxiliary_text when candidates are hidden.

Their visibility was controlled separately but r242610 changed
this.

This is intentionally false instead of is_auxiliary_text_visible()
of candidate_window_ because that field is not updated at that point.

BUG=332275
R=hsumita@chromium.org, komatsu@chromium.org
TEST=manually

Review URL: https://codereview.chromium.org/128863002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@243866 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 243866