Use image view when it's section header is a star

* Define mHeaderTextView as a View so that it can be ImageView and TextView
  and rename it as mHeaderView.
* Hide pinned header when it's a star.
* Move section header to left by 14dp and make text and image center aligned.
* Make section header size 16sp.
* Make star pink.

Bug 28426878

Change-Id: I1aa563e5201e41487a7edd7cd861a62d8b662ff5