[Offline Pages] Make new archives have random file names.
Currently offline pages with the same offline ID, title and URL will
produce archive files with the same filename. This leads to unexpected
circumstances where archives could be overwritten even if the offline
page model is not updated.
This improvement also allows for more reliable updates to existing offline
pages by making the update process 3-step: create an archive, then update
the offline page to point to the newly created archive, then clean up the
old archive.
BUG=638276
Review-Url: https://codereview.chromium.org/2579343002
Cr-Commit-Position: refs/heads/master@{#441243}
5 files changed
