ash: Increase shelf tooltip show up delay to 1s.

BUG=322928

Review URL: https://codereview.chromium.org/99613002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238187 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 238187