ash: Move TooltipManager to from launcher to shelf.

BUG=248353
TEST=none, no functional changes.
R=jamescook@chromium.org,xiyuan@chromium.org

Review URL: https://codereview.chromium.org/26124002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@227754 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 227754