[skottie] Expose WYSIWYG editing functionality in WASM/CK

Introduce ManagedAnimation APIs to support of live/WYSIWYG editing:

  attachEditor()
  enableEditor()
  dispatchEditorKey()
  dispatchEditorPointer()

In order to support attaching the editor to text nodes on demand, make
PropertyHandle copyable, and add CustomPropertyManager handle getters.


Bug: b/290019618
Change-Id: I35efcbfd7738fff0bea3f299f2cde0c4d30b5707
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/750345
Commit-Queue: Kevin Lubick <kjlubick@google.com>
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Auto-Submit: Florin Malita <fmalita@chromium.org>
14 files changed