Milanesi saw advantages in both operating systems and thought Google should not force consumers to choose. Instead, they should have the "aha" moment of recognition across devices that they increasingly get from Apple's Mac OS and iOS.

Analysts said they will also be on the lookout this week for possible new features on Google+, upgrades to Google Maps and improvements to Android security.

This year's Google I/O, which , will be the first to fill three days of programming. In response to the demand, Google plans to double the number of sessions it will livestream from San Francisco and put on 350 I/O Extended events, or conference viewing parties that sometimes host a keynote of their own.

The IDG News Service