Type A USB 3.0 with Type C USB 3.0 orientation:
The Type-A receptacle doesn't have CC pins, it is true. But the CC pins are present in the other end (Type-C) cable. The A-to-C adapter you described is called "legacy cable assembly", where the Type-C end represents host functionality (because Type-A receptacle is normally a USB host). To make the Type-C cable end to look like a host, the C-end includes a 56k resistor pulled to VBUS. The resistor is mounted inside the Type-C overmold. This signals to a Type-C device that a standard 500/900mA host is behind the cable, and everything works, in both orientations.