GitLab

This fixes two issues:
1) Set use_tab_for_suggestions_ at the end of OnAutocompleteStart so that it
doesn't get overridden by calls to HideOverlay.
2) If not using tab for suggestions, make sure the overlay is ready to use.

BUG=241835

Review URL: https://chromiumcodereview.appspot.com/15755011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@202966 0039d316-1c4b-4281-b951-d872f2087c98