We now use std::string_view throughout. SkStringView.h has been moved to
include/private/ and is only used for our C++20/23 compatibility methods
(starts_with/ends_with/contains).
Change-Id: I961842c6778256a03868e7602d48add34f420763
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/502306
Reviewed-by: Ben Wagner <bungeman@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
