remove SkDebugWStream and other cleanups

BUG=skia:

Change-Id: I06c07559b24411bd8bc4cba55bd8880f56486f76
Reviewed-on: https://skia-review.googlesource.com/6729
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
6 files changed