Adds method to PasswordStore which return origin in human readable form.
This is needed for Android URL representation. Currently, Android URL's have following form
android://m3HSJL1i83hdltRq0-o9czGb-8KJDKra4t_3JRlnPKcjI8PZm6XBHXx6zG4UuMXaDEZjR1wuXDre9G9zvN7AQw==@com.example.android
This looks bad on chrome://settings/passwords, so we need to put infrastructure in place which allows us to show
android://com.example.android instead.
BUG=437865
R=estade@chromium.org,engedy@chromium.org,mkwst@chromium.org
Review URL: https://codereview.chromium.org/
839803002
Cr-Commit-Position: refs/heads/master@{#311269}