Android itself is actually present on many China phones, but it's not the version that brings Google any revenue. Instead, handset makers there have relied on the AOSP, or Android Open Source Project, software combined with other China-based services and app stores.
Google simply can't ignore the massive population base China has and cede the market to plain vanilla Android handsets and - in growing numbers - Apple's iPhone, which does have its iTunes App Store available in the world's most populous nation.
The devil's in the details though. What modifications or concessions does Google have to make with China's government to bring the Google Play Store to that region?
Whatever they are, Google is likely to make them: Any larger mobile presence in China is better than what Google has today.