feedback: base::StringPiece -> std::string_view

Bug: 691162
Change-Id: I11ba8e6b0bda1465be82f59e920db5c6c79efc7f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5371939


Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Reviewed-by: Miriam Zimmerman <mutexlox@chromium.org>
Commit-Queue: Helmut Januschka <helmut@januschka.com>
Cr-Commit-Position: refs/heads/main@{#1279880}