On Thursday, Motorola Mobility Holdings Inc announced a sales setback in the 4th quarter, mirroring preliminary numbers that the company released three weeks ago. This announcement will affect Google shareholders more than those of Motorola because of a deal the two companies reached last summer. Google has agreed to pay $40 per share for Motorola’s vast patent portfolio, as well as its devices. Motorola Mobility may become a financial millstone that could drag down Google’s earnings growth. If that happens, Google’s stock price may suffer.