This news may surprise and intrigue SEO professionals.... Google announced that content within Android apps can now be indexed for search. The new capability is called app indexing. Specifically app indexing allows Android users who have a mobile app installed to open it directly from relevant mobile search results on Google.
App indexing allows web and mobile designers to connect pages from websites and content within Android mobile apps. Currently app indexing is enabled on the Google Search App version 2.8+ for Android 4.1+, as well as in mobile browsers on Android so long as the user is logged into their account. Currently the capability is not open to all publishers and developers. Google is giving the feature a trial run, but mobile developers can request to participate.
App indexing will expand the marketing possibilities for mobile apps--helping to shift a heavy dependance on PR and editorial to digital marketing methods like SEO. This may help drive even more interest around mobile app development.
SOURCE: https://developers.google.com/app-indexing/webmasters/