Are standard USB connectors (Standard / Mini / Micro) Impedance controlled?
The spec is not exactly 90Ω for connectors, but has a more loose requirement for impedance. Connectors that are built to the USB spec will have an impedance of the standard. The data lines inside of USB are twisted (or should be) which also makes an transmission line.

The way the manufacturers probably keep the impedance within spec is by modeling the parasitics and making a simple circuit. The pins to shell would form a capacitor and the pins have resistance and a small amount of inductance. If you do have a termination (like a connector, it is important to match closely but it doesn't have to be exactly matched, the goal is to minimize reflections and if you have an impedance close to 90Ω then that will be sufficient to maintain signal integrity. 

The USB spec calls for a mated connector impedance of 75Ω to 105Ω:


  Universal Serial Bus 3.1 Legacy Connectors and Cable Assemblies
  Compliance Document
  
  Mated Connector Impedance (Differential)
  
  75 Ω minimum, 105 Ω maximum. 50ps (20-80%) rise time of a differential
  TDR. (Mated connector includes cable termination areas). SuperSpeed
  pairs only.  


Source: https://www.usb.org/sites/default/files/CabConn_Legacy_3_1_Compliance_Rev_1_1.pdf