During his five years stint at Google, Barra had been the constant public face of Android. He demonstrated several new Android devices during their launch events including the second-generation Google Nexus 7 launched in July.

Xiaomi is known for portraying itself as China's answer to Apple Inc. Its flagship smartphone, the Mi 2S, was the most popular phone in China during the first half of the year, according to a popular benchmark service.

Xiaomi sold more smartphones than Apple did in the second quarter in China, the world's biggest smartphone market, according to IT consultancy Canalys.