Add support for automated credentials login in webpages_playback.py

Just a rollback of https://skia-review.googlesource.com/c/skia/+/84540/3/tools/skp/webpages_playback.py
because I figured out how to use it in page sets.

NoTry: true
Bug: skia:8896
Change-Id: I771e282f4de472ed0dbe02a22e2311bb98c2f9ba
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/202952
Commit-Queue: Ravi Mistry <rmistry@google.com>
Reviewed-by: Eric Boren <borenet@google.com>
1 file changed