Rumors had been swirling for weeks that HTC had a pair of new Android phones with deep Facebook integration in the offing, and now the two handsets—the Salsa and the ChaCha, both with their own, dedicated Facebook buttons—have finally been unveiled, Yahoo News reports. Details on the Salsa, which comes with a 3.4-inch display, and its little brother, the 2.6-inch ChaCha, are still a little sketchy; indeed, reporters and bloggers at HTC’s press conference at the Mobile World Congress show in Barcelona could only gaze at the two handsets through a pane of protective glass…