[Password Generation] Set TYPE_GENERATED to presaved credentials

Since a user accepts a password generated by Chrome, the password is presaved to the store. |PasswordForm.type| should be set to TYPE_GENERATED. This CL implements that.

It is important for metrics.

BUG=None

Review-Url: https://codereview.chromium.org/2893903002
Cr-Commit-Position: refs/heads/master@{#472805}
2 files changed