New numbers show Android-based tablets are gaining on the reigning champ, Apple’s iPad. Although Android owns 39 percent of the tablet market, some question whether there’s a ringer: Amazon’s Kindle Fire. The device is the first non-Apple tablet to lay a hand on the iPad, but uses a highly-customized version of Google’s mobile operating system. How much of Android’s gains are due to its barely-recognizable distant cousin, twice removed?