Introduce RenderNode::nodeAt(const SkPoint&) as the entry point for the hit-testing API.
This is backed by a onNodeAt() virtual, which gets dispatched throughout the render DAG,
and normally stops at the first leaf Draw node in encounters.
To support the implementation, introduce a GeometryNode::contains(const SkPoint&) API.
This is backed by a onContains() virtual, overridden in each concrete geometry class.
Expose nodeAt() on sksg::Scene, and add some basic unit tests.
Change-Id: I0c8abd9d1e51ecf2d8b4dd699f325cd636e21084
Reviewed-on: https://skia-review.googlesource.com/c/191296
Commit-Queue: Florin Malita <fmalita@chromium.org>
Reviewed-by: Mike Reed <reed@google.com>
eb46bd892d