GitLab

Reset tooltip_controller explicitly so that timer stops at shutdown.
Use tray_ reference in SystemTrayDelegate instead of going through ash instance.
Make sure delegates doesn't access tray after the tray has been deleted.

BUG=104998
TEST=none

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=131902

Review URL: http://codereview.chromium.org/9968101

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@132320 0039d316-1c4b-4281-b951-d872f2087c98