Support adding title texts to pqViewFrame.

We always had the API to set the title, but it never did anything. This
commit fixes it to add a label if a non-empty title is specified.

Change-Id: I4bb93a7fe0169946dbc4cac07311e41c28cc99e0
Merge topic 'support_view_frame_titles' into next

51f7fece Support adding title texts to pqViewFrame.