[MDBViz] Add tear off windows for the op list & main canvas window

Change-Id: I4086a17eafecccaf0bac34c850c249a5e4efc719
Reviewed-on: https://skia-review.googlesource.com/42524
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
3 files changed