The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/03ca5214d7334213c3ce73b011d6826a606f4af2

commit 03ca5214d7334213c3ce73b011d6826a606f4af2
Author: henrika <henrika@chromium.org>
Date: Mon Jan 21 14:21:29 2019

Disables UsingRealWebcam_XXX tests on Mac OS X

TBR=chfremer

No-Try: true
Bug: 923874
Change-Id: I083f947ffc6a1bf9bec987d2461e42b09aef38b6
Reviewed-on: https://chromium-review.googlesource.com/c/1424949
Commit-Queue: Henrik Andreasson <henrika@chromium.org>
Reviewed-by: Mirko Bonadei <mbonadei@chromium.org>
Cr-Commit-Position: refs/heads/master@{#624580}
[modify] https://crrev.com/03ca5214d7334213c3ce73b011d6826a606f4af2/media/capture/video/video_capture_device_unittest.cc

This could potentially be quite interesting.

[ RUN      ] VideoCaptureDeviceTests/VideoCaptureDeviceTest.UsingRealWebcam_CaptureWithSize/0
../../media/capture/video/video_capture_device_unittest.cc:529: Failure
Value of: descriptor
  Actual: false
Expected: true

This indicates that no camera was found. Do these run on a desktop mac machine with an attached USB webcam, or do they run on a Macbook with integrated camera?

I don't know. Oleh can you take a look at message #3?

Another question: It seems the Mac Tester does not run anything for content_browsertests, content_browsertests_sequential, and content_browsertests_stress. I am not sure why.

I was hoping it would be running the test at [1], which produces a log output from which we can the name of the camera being used.

[1] https://cs.chromium.org/chromium/src/content/browser/webrtc/webrtc_image_capture_browsertest.cc?q=UsingRealWebcam&dr=C&l=83