Google announced that it is now ranking and indexing content within apps that do not have web content matches. Previously Google would only rank content within an app if there was a canonical version of the page on the mobile web. But now for android apps, as long as you are using Google App Indexing API, Google will be able to understand the content in the app and rank it in search results even if you don’t have a web URL. Currently, this is only true for Android Apps and seems to be in the beginning stages but Google plans to roll out more if it tests well in the initial stages. Google has currently launched this with nine apps for English US results as a test to see the impact on mobile searches.
Google has built a player that will stream your android app to android searchers, with android L or higher and a Wifi connection, even if they do not have your app installed. This is very helpful because it will get your app in its full state running on a user’s Android device even before they install it, in the hope users will eventually install the app on their device. Google will stream the content from the apps without requiring searchers to download the actual app.