Many Android apps display web content within the app. This prevents users from jumping back and forth between the app and browser when tapping a link in Gmail, for example. One way to do this, he said, is with the WebView component, but Google thinks Custom Tabs is a better solution, and with some improvements, it’s even better.
The first is a partial custom tab. Instead of filling the entire screen, web content can now only cover half. This will improve your multitasking experience as you can still use the app (e.g. keep reading your email). You can get the same effect using things like split screen mode, but that requires extra manipulation. The app developer determines the initial size of partial tabs, but users can choose to make them full screen if desired.
Custom tabs are a feature provided by your web browser of choice. If the browser does not support partial custom tabs, full-screen tabs are used instead. Apparently Chrome supports this feature, but so do other browsers.
However, if you choose Chrome, custom tabs support normal Chrome features such as autofilling text and password fields.
Source | Via
