Right now, Java is the only first-class programming language for Android, and reports claim that Google isn't looking to replace Java, at least not at first. The theory is that because of the ongoing litigation issues with Oracle over Google's use of Java, the company may be looking for a new option. Swift has been found to be very fast, and since it is open source, Google could use it without issue. It is also possible that Android using Swift could cut down the number of apps that launch on iOS before Android.
According to reports, representatives for Google, Facebook, and Uber met at the end of last year in London to discuss how each company could adopt Swift. Facebook and Uber were allegedly thinking about making it "more central to operations", while Google was thinking about supporting it more aggressively in Android.
Of course, even if Google were to do so, it would be a long and involved process because it would need to rewrite a lot of Android code and APIs. So, considering it is still only something in discussion, we won't expect any announcements all that soon.
source: The Next Web