Huawei starts testing Android O on the Mate 9
Picture-in-picture mode available in Android O only
The same goes for the Mate 9, the smartphone that Huawei chose for the testing of the yet unreleased version of Android. The Chineses handset maker has already released internal builds of Android O for its flagship phablet as is tries to attune EMUI to the requirements of the new operating system.
However, these internal builds that circulate among testers miss important features that would allow them to be used as daily drivers. For example, the Google Play Store doesn't work unless you're enough of a tech-savvy and sideload Google Play Services after installing the test build.
Also, there are only two language options that come with the Android O build: English and Chinese (Mandarin). On the bright side, Huawei added a couple of new files app and developer options.
Hopefully, Huawei will be able to push Android O to the Mate 9 soon after Google releases the final version. The main takeaway is that the Chinese company is determined to provide customers with new major updates ahead of other non-Google Android OEMs.
source: XDA Developers