Editor::copy() now writes into a buffer provided by the client.
Editor::text() now returns a series of `pair<const char*, size_t>`
instead of `const StringSlice&`
Change-Id: Iff298dd7a80aaad19f9326d10c5b67bea5ef8e22
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/232579
Commit-Queue: Hal Canary <halcanary@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>
