Text Editor based on SkText: delete and backspace

Change-Id: I1152f83af724634f06e1a767ef39bef2afe70b33
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/430656
Reviewed-by: Julia Lavrova <jlavrova@google.com>
Commit-Queue: Julia Lavrova <jlavrova@google.com>
4 files changed