Update image filter debug samples to use new APIs

For clarity, this renames skif::Mapping::Make to skif::Mapping::DecomposeCTM
to really emphasize when it should be used over just a constructor.

Renames SampleBackdropBounds to SampleFilterBounds since the operations and
coordinate spaces that it visualizes are the same for regular or backdrop
filtering (we just swap the notion of src and dst devices, really).
Technically, this is not quite true yet since regular filtering modifies the
DAG with a matrix transform right now, but that's going away soon (tm).

The "new" SampleFilterBounds example is updated to use the new bounds APIs
that use the coord-space safe types in the skif namespace. It also visualizes
a filter, and simplifies some of the bounds being drawn and reported to
only those most interesting.

The SampleImageFilterDAG has been updated to match the soon-to-be state
of how SkCanvas processes regular image filters for a saveLayer. All
implicit matrix-transform node code is removed. The bounds calculation
code is similarly updated to use the new 'skif' types and functions. To
simplify the visualization of each node, the 'isolated' versions of the
bounds were dropped.

Bug: skia:9282, skia:9283
Change-Id: If2ad2c302e5165ae009bba93cea52bf0566a543a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/326718
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
Auto-Submit: Michael Ludwig <michaelludwig@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>
6 files changed