[skottie] Add warning for missing text/paragraph box

Text auto-scaling requires an explicit paragraph box.

Change-Id: If3ba91051cd5fa8456fc8530d7ed7ad4c663fff9
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/272119
Commit-Queue: Florin Malita <fmalita@chromium.org>
Commit-Queue: Ben Wagner <bungeman@google.com>
Auto-Submit: Florin Malita <fmalita@chromium.org>
Reviewed-by: Ben Wagner <bungeman@google.com>
1 file changed