tree 0eed532236f2d8bf4fbbf040d1eb73b3d385653a
parent a8a43dbd12c3bd81b15860723b911037e601a35b
author Winson Chung <winsonc@google.com> 1449847566 -0500
committer Winson Chung <winsonc@google.com> 1450121001 -0500

Only show historical tasks in history.

- Also only show the history button if there are
  historical tasks (and reflect that in the 
  button text)

Change-Id: I7b9dcf79e2feef61f96b720f586144de4c5033e3