All of SkDrawCommand / SkDebugCanvas now uses SkJSONWriter.
Also removed the bespoke json generator and pretty-printer
in GrAuditTrail. This was the largest volume of code still
using JsonCPP. (There are other stragglers).
Bug: skia:
Change-Id: I3aee554764689ce50c8e707caf26c76093b9bb8f
Reviewed-on: https://skia-review.googlesource.com/c/187040
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>
d8a90f9be1