From 5.1.1:
The account deletion option should be easy to find in your app.
Is including deletion in the "Settings" section sufficiently "easy to find"?
People should be able to delete the account along with their personal data.
How much of this action must be enabled within the app?
From the update
all apps that allow for account creation must also allow users to initiate deletion of their account from within the app
What constitutes initiating deletion? Is clicking a button that takes you to a pre-filled email requesting deletion sufficient?