Assigning to Ovidio since I suspect https://chromium-review.googlesource.com/985195 may have caused this.

Ovidio please re-route this bug (or un-assign yourself) in case I'm wrong.

Linux seems to be effected to since: https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Linux%20Tests/68766

See:
https://logs.chromium.org/v/?s=chromium%2Fbuildbucket%2Fcr-buildbucket.appspot.com%2F8950744204030950832%2F%2B%2Fsteps%2Fsite_per_process_webkit_layout_tests%2F0%2Fstdout

Error snippet:
22:59:02.176 2137 worker/3 bluetooth/requestDevice/chooser/new-scan-device-added.html crashed, (stderr lines):
22:59:02.176 2137   [11147:11147:0328/225902.128675:ERROR:validation_errors.cc(87)] Invalid message: VALIDATION_ERROR_MESSAGE_HEADER_UNKNOWN_METHOD
22:59:02.176 2137   [11147:11147:0328/225902.128764:ERROR:render_process_host_impl.cc(4299)] Terminating render process for bad Mojo message: Received bad user message: Validation failed for FakeBluetoothChooser RequestValidator [VALIDATION_ERROR_MESSAGE_HEADER_UNKNOWN_METHOD]
22:59:02.176 2137   [11147:11147:0328/225902.128794:ERROR:bad_message.cc(25)] Terminating renderer for bad IPC message, reason 123

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/6d7c7f1d23765d53ee766da1dec00c6255338a93

commit 6d7c7f1d23765d53ee766da1dec00c6255338a93
Author: Markus Heintz <markusheintz@chromium.org>
Date: Thu Mar 29 11:25:42 2018

Disable crashing layout test bluetooth/requestDevice/chooser/new-scan-device-added.html on Mac

Bug:  827088 
Change-Id: Iab890ec3a1626e75b1a31f2e5b368ee7ab082a83

TBR=ricea

Change-Id: Iab890ec3a1626e75b1a31f2e5b368ee7ab082a83
Reviewed-on: https://chromium-review.googlesource.com/986092
Reviewed-by: Markus Heintz <markusheintz@chromium.org>
Commit-Queue: Markus Heintz <markusheintz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#546788}
[modify] https://crrev.com/6d7c7f1d23765d53ee766da1dec00c6255338a93/third_party/WebKit/LayoutTests/TestExpectations

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/301bfef4bdf5e226c0d82f84a40ad6fab871c986

commit 301bfef4bdf5e226c0d82f84a40ad6fab871c986
Author: Markus Heintz <markusheintz@chromium.org>
Date: Thu Mar 29 12:26:15 2018

Disable bluetooth/requestDevice/chooser/new-scan-device-added.html  on all platforms.

Bug:  827088 
Change-Id: Icc9c4d6cca7b4266a28577371e29b0e9ca297555

TBR=ricea

No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Change-Id: Icc9c4d6cca7b4266a28577371e29b0e9ca297555
Reviewed-on: https://chromium-review.googlesource.com/986256
Commit-Queue: Markus Heintz <markusheintz@chromium.org>
Reviewed-by: Markus Heintz <markusheintz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#546793}
[modify] https://crrev.com/301bfef4bdf5e226c0d82f84a40ad6fab871c986/third_party/WebKit/LayoutTests/TestExpectations

The test is also failing on Win and Linux

https://ci.chromium.org/buildbot/chromium.webkit/WebKit%20Win10/32813

https://logs.chromium.org/v/?s=chromium%2Fbb%2Fchromium.webkit%2FWebKit_Win10%2F32813%2F%2B%2Frecipes%2Fsteps%2Fwebkit_layout_tests_on_Windows-10-14393%2F0%2Fstdout

-------------- Error snippet ----

22:46:18.605 2176 killed pid 1576
22:46:18.608 2176 worker/6 bluetooth/requestDevice/chooser/new-scan-device-added.html crashed, (stderr lines):
22:46:18.608 2176   [1576:424:0328/224617.821:ERROR:validation_errors.cc(87)] Invalid message: VALIDATION_ERROR_MESSAGE_HEADER_UNKNOWN_METHOD
22:46:18.608 2176   [1576:424:0328/224617.822:ERROR:render_process_host_impl.cc(4299)] Terminating render process for bad Mojo message: Received bad user message: Validation failed for FakeBluetoothChooser RequestValidator [VALIDATION_ERROR_MESSAGE_HEADER_UNKNOWN_METHOD]
22:46:18.608 2176   [1576:424:0328/224617.822:ERROR:bad_message.cc(25)] Terminating renderer for bad IPC message, reason 123
22:46:18.611 5664 [2031/10408] bluetooth/requestDevice/chooser/new-scan-device-added.html failed unexpectedly (renderer crashed)

All green on flakiness dashboard, removing from sheriff queue.

https://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType=webkit_layout_tests&tests=new-scan-device-added.html