1. What is the only change we did NOT have to make to use authentication?
Make sure the package name matches what you used to generate the Android client id
Add the client id of the Android client to the credentials object
Add the client id of the web client to the credentials object
Add permissions for credentials, internet, and account pickers to the manifest
Use the credentials when building the service

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2. Which client ID do we need to add to the credentials object?
The id of the Android client
The id of the web client

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