That's not quite right. A real in-app browser on Android, like Facebook's, has fully independent state. But Android also supports a feature called Custom Tabs,

That's not quite right. A real in-app browser on Android, like Facebook's, has fully independent state. But Android also supports a feature called Custom Tabs, where you can have something that looks an acts a lot like an in-app browser but is actually your default browser under the hood. The embedding app gives up some control over it, and can't for example, inject custom JavaScript, but in exchange it shares state with the default browser. More: https://developer.chrome.com/docs/android/custom-tabs/ https://developer.chrome.com/docs/android/custom-tabs/