Failed here:

https://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_dbg_ng/builds/1804

Log:

DevToolsSanityTest.TestDeviceEmulation (run #1):
[ RUN      ] DevToolsSanityTest.TestDeviceEmulation
[4444:4908:1111/073734:INFO:media_foundation_video_encode_accelerator_win.cc(307)] Windows versions earlier than 8 are not supported.
HTTP server started on http://127.0.0.1:50944...
sending server_data: {"host": "127.0.0.1", "port": 50944} (36 bytes)
[4692:4200:1111/073739:INFO:CONSOLE(0)] "Long running JavaScript task took 75ms.", source:  (0)
[4692:4200:1111/073741:INFO:CONSOLE(0)] "Long running JavaScript task took 161ms.", source:  (0)
[2860:3828:1111/073742:ERROR:csscomputedstyledeclaration.cpp(271)] Blink does not yet implement getComputedStyle for 'background-repeat-x'.
[2860:3828:1111/073742:ERROR:csscomputedstyledeclaration.cpp(271)] Blink does not yet implement getComputedStyle for 'background-repeat-y'.
[2860:3828:1111/073742:ERROR:csscomputedstyledeclaration.cpp(271)] Blink does not yet implement getComputedStyle for 'quotes'.
[2860:3828:1111/073742:ERROR:csscomputedstyledeclaration.cpp(271)] Blink does not yet implement getComputedStyle for 'size'.
[2860:3828:1111/073742:ERROR:csscomputedstyledeclaration.cpp(271)] Blink does not yet implement getComputedStyle for '-webkit-mask-repeat-x'.
[2860:3828:1111/073742:ERROR:csscomputedstyledeclaration.cpp(271)] Blink does not yet implement getComputedStyle for '-webkit-mask-repeat-y'.
[2860:3828:1111/073742:ERROR:csscomputedstyledeclaration.cpp(271)] Blink does not yet implement getComputedStyle for '-webkit-perspective-origin-x'.
[2860:3828:1111/073742:ERROR:csscomputedstyledeclaration.cpp(271)] Blink does not yet implement getComputedStyle for '-webkit-perspective-origin-y'.
[2860:3828:1111/073742:ERROR:csscomputedstyledeclaration.cpp(271)] Blink does not yet implement getComputedStyle for '-webkit-transform-origin-x'.
[2860:3828:1111/073742:ERROR:csscomputedstyledeclaration.cpp(271)] Blink does not yet implement getComputedStyle for '-webkit-transform-origin-y'.
[2860:3828:1111/073742:ERROR:csscomputedstyledeclaration.cpp(271)] Blink does not yet implement getComputedStyle for '-webkit-transform-origin-z'.
[2860:3828:1111/073742:ERROR:csscomputedstyledeclaration.cpp(271)] Blink does not yet implement getComputedStyle for 'all'.
[2860:3828:1111/073742:ERROR:csscomputedstyledeclaration.cpp(271)] Blink does not yet implement getComputedStyle for 'page'.
[2860:3828:1111/073742:ERROR:csscomputedstyledeclaration.cpp(271)] Blink does not yet implement getComputedStyle for '-webkit-font-size-delta'.
[4692:4200:1111/073743:ERROR:CONSOLE(67)] "Uncaught TypeError: Cannot read property 'addExtensions' of undefined", source: chrome-devtools://devtools/bundled/devtools_compatibility.js (67)
[4692:4200:1111/073748:INFO:CONSOLE(0)] "Long running JavaScript task took 76ms.", source:  (0)
[4692:4200:1111/073748:INFO:CONSOLE(0)] "Long running JavaScript task took 145ms.", source:  (0)
e:\c\win\src\chromerowser\devtools\devtools_sanity_browsertest.cc(141): error: Value of: result
  Actual: "[FAILED] Wrong metrics for params: {"width":1200,"height":1000,"deviceScaleFactor":3,"mobile":false,"fitWindow":true}(Expected: '"{"width":1200,"height":1000,"deviceScaleFactor":3}"', but was '[Violation] Long running JavaScript task took 76ms.')"
Expected: "[OK]"
[4692:4200:1111/073750:WARNING:url_request_context_getter.cc(43)] URLRequestContextGetter leaking due to no owning thread.
[  FAILED  ] DevToolsSanityTest.TestDeviceEmulation, where TypeParam =  and GetParam() =  (17477 ms)


Not sure whether this was failing reliably at the time and something was reverted, a one-off flake, etc. No bug filed about this at the moment.