The actual blamelist comparing
https://build.chromium.org/p/chromium.webrtc/builders/Win8%20Tester/builds/35161 (commit position 480973)
with
https://build.chromium.org/p/chromium.webrtc/builders/Win8%20Tester/builds/35162 (commit position 481003)
and looking at the parent_got_revision property is:
https://chromium.googlesource.com/chromium/src/+log/451245fd167ca58e0a604c7b0b94df4d5070e794..4f4375e33e98c4ca5736470469638759e8b3940c

I don't know why that is, the only case where things like that should be able to happen is when the builder has failed to build. That seems to actually have happened here:
https://build.chromium.org/p/chromium.webrtc/builders/Win%20Builder/builds/57269 (commit position 480996)
https://build.chromium.org/p/chromium.webrtc/builders/Win%20Builder/builds/57270 (commit position 481002)

which explains the confusing blame list. Bad luck, but opens up for identifying the culprit!

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/109eab7e4104da3f5ae4c5387a1ce54e6b74e0ab

commit 109eab7e4104da3f5ae4c5387a1ce54e6b74e0ab
Author: Sami Kalliomäki <sakal@chromium.org>
Date: Wed Jun 21 11:27:06 2017

Revert "[Video/Image Capture] Put Windows image capture controls behind feature flag"

This reverts commit f21fba7db4b89356077c052c49b165f3e48c9305.

Reason for revert: Speculatively reverting, might have caused
chromium.webrtc tests to start failing. Failing tests:
https://build.chromium.org/p/chromium.webrtc/builders/Win8%20Tester/builds/35162
https://build.chromium.org/p/chromium.webrtc/builders/Win10%20Tester/builds/17320

Original change's description:
> [Video/Image Capture] Put Windows image capture controls behind feature flag
> 
> The drivers for several devices on Windows appear to not properly handle
> querying for controls used in the context of Image Capture. These cases lead to
> video capture being broken and users seeing only a blank image.
> 
> This CL adds a feature flag kImageCaptureControls Image Capture on Windows. 
> For now, we disable this feature by default. The feature can be enabled by 
> adding --enable-features=ImageCaptureControls to the command-line.
> 
> Bug:  722038 
> Test: Manual tested on Windows using iSpy virtual device.
> Change-Id: I654ff72772af10c2d5356d5131ed7ed98e300c1f
> Reviewed-on: https://chromium-review.googlesource.com/530076
> Reviewed-by: Dan Sanders <sandersd@chromium.org>
> Reviewed-by: Emircan Uysaler <emircan@chromium.org>
> Commit-Queue: Christian Fremerey <chfremer@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#480999}

TBR=mcasas@chromium.org,sandersd@chromium.org,emircan@chromium.org,chfremer@chromium.org

Change-Id: I12d976ca1c81c55a685360bb23817dca605085ad
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug:  722038 ,  735379 
Reviewed-on: https://chromium-review.googlesource.com/543137
Reviewed-by: Henrik Kjellander <kjellander@chromium.org>
Commit-Queue: Sami Kalliomäki <sakal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#481173}
[modify] https://crrev.com/109eab7e4104da3f5ae4c5387a1ce54e6b74e0ab/content/browser/webrtc/webrtc_image_capture_browsertest.cc
[modify] https://crrev.com/109eab7e4104da3f5ae4c5387a1ce54e6b74e0ab/media/base/media_switches.cc
[modify] https://crrev.com/109eab7e4104da3f5ae4c5387a1ce54e6b74e0ab/media/base/media_switches.h
[modify] https://crrev.com/109eab7e4104da3f5ae4c5387a1ce54e6b74e0ab/media/capture/video/win/video_capture_device_factory_win.cc
[modify] https://crrev.com/109eab7e4104da3f5ae4c5387a1ce54e6b74e0ab/media/capture/video/win/video_capture_device_win.cc
[modify] https://crrev.com/109eab7e4104da3f5ae4c5387a1ce54e6b74e0ab/media/capture/video/win/video_capture_device_win.h