That's the date when Google announced that they were intending to buy Motorola, but such an announcement is irrelevant. Until the deal closes, the companies are legally obligated to continue behaving as if nothing has changed. For example in this case there were anti-trust issues in at least China and the US.

According to Wikipedia pages the dates were:

http://en.wikipedia.org/wiki/Droid_X: On May 19, 2011, Motorola released the Droid X2

http://en.wikipedia.org/wiki/Motorola_Mobility#Acquisition_b...: The deal received subsequent approval from Chinese authorities and was completed on May 22, 2012.

That's over a year, if barely.