Mozilla is following in what is becoming a grand tradition in the mobile world ‘ hunting for a new CEO for almost a year and then choosing to promote someone who was there all along. Brendan Eich, a co-founder who has been the browser designer’s CTO since 2005, will now take the top spot, and will put the new mobile Firefox OS at the heart of the strategy. Eich may be a inside choice, but his promotion spells change at Firefox, and particularly a redoubled effort behind making the mobile platform a genuine challenger to Google. Some are reporting the move to increase Firefox OS’s profile within Mozilla as a move away from its core browser, but of course, it…