[Mac] Editor Crashes/Freezes while trying to access the webcam if scripting backend is Mono.

1. Open attached project.
2. Make sure the cube has the webcam script attached to it. If it doesn't, manually add the script to the cube.
2. Make Sure the scripting backend is set to Mono.(It is Mono by default)
3. Attach a webcam to the system.
4. Hit the play button in the editor.

Note: Checked for a standalone/android build, Observed crash.

Expected Result: Live video from the webcam should be rendered on the cube.

Observed Result: Editor Freezes/Crashes

Reproducible On: 2019.1.0a12

Not Reproducible On: 2019.1.0a11, 2018.3.0f2

Environment:
Occurs Only On Mac