custom-tab-oauth demo: Chrome Custom Tab remains open with Oath redirect url instead of opening the MainActivity

[cpjoshi]

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Describe the bug

1. OAuth redirect is not working in the given example.
2. custom-tab-oauth example is supposed to show how github oauth authentication can be done with Chrome Custom Tabs (CCT). But CCT never closes and control is never passed back to MainActivity

To Reproduce

• Add the correct clientId and Secret for github OAuth client setup in code.
• Start the application in AVD emulator.
• MainActity opens.
• Click on Login, CCT is opened and github login page is shown.
• Login to github and complete the consent process.
• After successful consent flow the CCT opens the redirect url: https://oauth-custom-tabs.glitch.me/oauth/auth-callback.html and stay here.

Expected behavior
Since the MainActivity has configured intent-filter filter OAuth callback url (https://oauth-custom-tabs.glitch.me/oauth/auth-callback.html), when github redirects to this URL, the MainActivity should open for further OAuth flow processing.

Did this ever used to work
n/a

Screenshots

Code Snippets
If applicable, add or link to code snippets describing how the API is being used.

Smartphone (please complete the following information):

• Device: Pixel 2, API-29
• OS: Android 10
• Browsers Installed: Chrome
• Browser Versions: 74.0.3729.185
• android-browser-helper library version: Latest

Additional context
Add any other context about the problem here.

[andreban]

Handling the callback relies on configuring App Links for the Android app and the callback origin, so it won't work unless you test it on your own origin and setup App Links.