Andy Rubin, the brains behind the Google Android operating system which has become the dominant mobile platform, is stepping down as head of that division, the company said Wednesday.

Google chief Larry Page announced that Sundar Pichai, the head of its Chrome laptop unit, will take over the team in charge of Android software for smartphones and tablet computers.

"Andy's decided it's time to hand over the reins and start a new chapter at Google," Page said, not specifying what Ruben's new post is.

Under Rubin, Android became the leading platform worldwide for smartphones, accounting for some three-fourths of the market, and has become a major force in tablet computers as well.

"While Andy's a really hard act to follow; I know Sundar will do a tremendous job doubling down on Android as we work to push the ecosystem forward."

Pichai is adding Android development to his duties overseeing Chromebooks fielded as a cloud-based alternative to traditional computers, Page said in a blog post.

It was unclear what the leadership change regarding the potential for bringing together Chrome and Android operating systems.

Google has pursued both platforms, with Chrome software designed for laptops that serve essentially as gateways to services hosted in the Internet cloud and Android a popular, and free, engine for powering mobile devices.

Pichai presided over the debut last month of a touchscreen Chromebook Pixel designed for high-end users, throwing down the gauntlet to Apple and its MacBooks.

At a launch event, Pichai said Google planned to continue pursuing a dual strategy with Android and Chrome.

"Sundar has a talent for creating products that are technically excellent yet easy to use, and he loves a big bet," Page said.

"Today Chrome has hundreds of millions of happy users and is growing fast thanks to its speed, simplicity and security."

Chromebooks were introduced in 2008 as a low-cost alternative to laptop computers.