These failures also appear on our official+branded win64 clang tot bot:
https://ci.chromium.org/buildbot/chromium.clang/ToTWin64/1134

It has crrev.com/544557 in the blame as well.

Was this fixed by crrev.com/544770?

I wasn't able to reproduce these widevine test failures locally. I guess we'll see if the next build comes back green.

Should be caused by one of my CLs. I'll take a look.

Re #3: I don't believe crrev.com/544770 will fix it. I suspect this is a swarming issue where the CDM is not send to the testing bots (pure guess). Trying to repro locally now.

re c#6: Ah, not sending the file via swarming seems much more plausible. I ran the tests locally without swarming and they passed.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/1a833a9a64ff54b3eee785705356a759637991a6

commit 1a833a9a64ff54b3eee785705356a759637991a6
Author: Xiaohan Wang <xhwang@chromium.org>
Date: Thu Mar 22 21:27:26 2018

media: Widevine CDM binary/manifest as data_deps of "cdm" target

The swarming client needs this data_deps to put the CDM files in the
isolate (send them to the swarming bot).

We still need to keep the public_deps since it's needed to build the mac
bundle.

Bug:  772160 , 824493 

Test: Tested locally on a Linux box with is_chrome_branded, following
instructions on how to generate swarming isolate locally:
https://www.chromium.org/developers/testing/isolated-testing/for-swes#TOC-Run-a-test-built-locally-on-Swarming
More specifically, I tried load_library_perf_tests, which also depend on
the "cdm" target:
- ninja -C out/Debug -j1000 load_library_perf_tests
- echo gn > out/Debug/mb_type
- tools/mb/mb.py isolate //out/Debug load_library_perf_tests
With the fix, libwidevinecdm.so is in the isolate file.

Change-Id: I68f62a819302be811944614292db447c601cadcb
Reviewed-on: https://chromium-review.googlesource.com/976384
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Commit-Queue: Xiaohan Wang <xhwang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#545256}
[modify] https://crrev.com/1a833a9a64ff54b3eee785705356a759637991a6/third_party/widevine/cdm/BUILD.gn

Thanks! I attempted to build browser_tests locally and run the tests via swarming like the bots do, but it was a complete failure. :(