Remove defunct SkJSCanvas

Added disabled in 8ea69838a4f00281c744e8c8e7fc95375c0aa1e5 and appears
to never have been used. This seems now very superseded by CanvasKit.

Change-Id: I0fd3a8b2dc3a7207b8fa6ae9205842e4f5df450e
Reviewed-on: https://skia-review.googlesource.com/c/194604
Auto-Submit: Ben Wagner <bungeman@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
Reviewed-by: Mike Reed <reed@google.com>
1 file changed