Automatic distinction between PC-USB and Wall Adapter-USB
There are two main ways that USB high current is indicated (Apple's way and everyone else.)

Apple uses a resistor divider to set D+ and D- at various voltages to indicate between 500mA and near 2A charge.  1.1 and 1.5A I think in there.  I would have to think if this puts a kink to below if you use an Apple charger.

Everyone else shorts D+ and D- together.  Many USB charge controllers handle the detection on the USB data lines.  If you are making a one of device, that is an easier route.

For your own detection, tie D+ to VCC with 10k resistor.  Tie D- to GND with 100k resistor.  Read D-, if high you can pull high current.  If low, you can't.  

For your Mouser linked chip: Pull EN2 low with 10k resistor.  Connect D- to EN1 to enable full current if data lines shorted or 100mA if not.