At the Google I/O 2015 keynote address, Google is moving fluidly between broad Android improvements for the upcoming M preview build and more specific improvements for the company's apps and APIs. One of the first reveals was for a new Chrome feature, Chrome Custom Tabs. This is basically a more robust alternative to embedding a web view in an app, adding a minimal and customized window of Google Chrome on top of the active app.
The demonstration on stage was with Pinterest. When a user clicked on web content (something that would normally pop out to a new Chrome tab or apply a minimal web view inside the app), a Custom Tab launches instead. This is a minimal Chrome tab that's sort of "stuck" on top of the app itself. The app and the user have access to all of Chrome's rendering capabilities, saved passwords, auto-fill from the keyboard, and all of Chrome's security features.
According to the presenter, Chrome Custom Tabs are available to developer build users starting today, and will launch on the stable version of Chrome for Android (and any app that uses the feature) sometime on the third quarter of this year.
Google has posted more information on the new Chrome custom tabs feature on its developer page. The big advantages are more effectively laid out, namely some user interface customizations, new animations, custom menu items, and the "shared cookie jar" function that allows Chrome and the app to share login and other information.
Google's developer page has some tips on adding Chrome custom tabs to your apps. Here's the GitHub page, and you can check it out in action with the latest Chrome for Android Dev build. Chrome custom tabs should be available in the stable builds later this year.