New member, here. I'm thankful I came across this thread! I just got a Galaxy Nexus and was having problems getting my (supposedly) Dual 1A Griffin PowerJolt to be recognized as an AC charge source. I shorted the pins as described and it worked!
I then proceeded to do the Palm Touchstone Inductive charge mod. Works great then touchstone is plugged into my Wall charger that came with the nexus so I know the cable works and the touchstone works. I could not however get it to charge on the 12V car charger modded to show itself as an AC charge source. I opened it up again and measured resistance between data pins and power/gnd. On the 12V charger there was a few kOhms between data and power pins so the data lines are being pulled to 2.5V. On my wall charger the data to power is open. So I found the 4 resistors on the 12V charger pulling the pins to 2.5V and verified they were now floating (open to pwr/gnd) and the 12V charger now powers the touchstone. I have not been able to verify if this will yield a faster charge on the phone directly connected but I thought I'd share because it did make a difference not having the data pins tied to pwr/gnd (despite being shorted to each other)