Add markCTM(id) api, to replace functionality of saveCamera.

Will need followups on Vertices and SkSL to use these handles.

Change-Id: If775cb01168f601541e889bfa2421129e505b4a4
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/282416
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
18 files changed