This CL skips passwords which don't exist in the keychain during
migration to OSCrypt. They are deleted from the database instead because
the error is permanent and current Stable Chrome just filtered them out.

(cherry picked from commit 43f5aced562e1ca31da893e9e286f1daaa5ef52e)

Bug: 1472526
Change-Id: Iddebf0475f956108118c75a8c25ceb07300c88c4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4835913
Reviewed-by: Vasilii Sukhanov <vasilii@chromium.org>
Commit-Queue: Viktor Semeniuk <vsemeniuk@google.com>
Cr-Original-Commit-Position: refs/heads/main@{#1191342}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4834504
Commit-Queue: Harry Souders <harrysouders@google.com>
Owners-Override: Harry Souders <harrysouders@google.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/branch-heads/5984@{#4}
Cr-Branched-From: f45ff4f1b1544181bf9db83fd296c8f20b595f53-refs/heads/main@{#1191262}