Google is buying Motorola Mobility’s video equipment factory in Horsham, as well as its Smartphone plants and a portfolio of patents. The Horsham business represents about one third of the telecommunications company’s annual sales. The price is about $12 1/2 billion. The leading internet search-engine company is adding about 20,000 workers at Motorola factories to its own workforce of nearly 30,000. With the Motorola Mobility purchase, Google gets a major manufacturer for its Android-brand Smartphone systems, other broadband and digital-video equipment, and more than 15,000 patents for various telecom devices. Google makes the Smartphone software, and Motorola makes hardware to go with it. The deal still needs federal government approval.