Telemetry rolls started failing earlier today (see https://github.com/catapult-project/catapult/issues/2455 ) because telemetry.internal.browser.browser_unittest.BrowserTest.testCloseReferencedTab started flakily failing on Linux. Here is just one example failing build:

https://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_rel_ng/builds/257759

Here's the stack trace:

  *************** BROWSER STANDARD OUTPUT ***************
  [1:1:0706/082836:ERROR:memory_mapped_file.cc(52)] Couldn't open /tmp/isolated_runE_2mpZ/out/Release/chrome_200_percent.pak
  [1:1:0706/082836:ERROR:data_pack.cc(80)] Failed to mmap datapack
  Xlib:  extension "RANDR" missing on display ":9".
  [13744:13744:0706/082836:ERROR:memory_mapped_file.cc(52)] Couldn't open /tmp/isolated_runE_2mpZ/out/Release/chrome_200_percent.pak
  [13744:13744:0706/082836:ERROR:data_pack.cc(80)] Failed to mmap datapack
  Xlib:  extension "RANDR" missing on display ":9".
  [13782:13782:0706/082836:ERROR:sandbox_linux.cc(343)] InitializeSandbox() called with multiple threads in process gpu-process. 
  [13744:13765:0706/082836:ERROR:browser_gpu_channel_host_factory.cc(131)] Failed to create channel.
  [13744:13744:0706/082837:FATAL:resource_provider.cc(1189)] Check failed: false. Image not valid
  #0 0x7f66fd26e1de base::debug::StackTrace::StackTrace()
  #1 0x7f66fd28601b logging::LogMessage::~LogMessage()
  #2 0x7f66fdf6c160 cc::ResourceProvider::ScopedReadLockSkImage::ScopedReadLockSkImage()
  #3 0x7f66fe0172d4 cc::SoftwareRenderer::DrawTileQuad()
  #4 0x7f66fe015a9b cc::SoftwareRenderer::DoDrawQuad()
  #5 0x7f66fe0530f5 cc::DirectRenderer::DrawRenderPass()
  #6 0x7f66fe05240c cc::DirectRenderer::DrawRenderPassAndExecuteCopyRequests()
  #7 0x7f66fe0521ac cc::DirectRenderer::DrawFrame()
  #8 0x7f66fe32ca72 cc::Display::DrawAndSwap()
  #9 0x7f66fe32e6d9 cc::DisplayScheduler::DrawAndSwap()
  #10 0x7f66fe32da46 cc::DisplayScheduler::OnBeginFrameDeadline()
  #11 0x7f66fd2b0a51 _ZN4base8internal7InvokerINS0_9BindStateIMNS_7RunLoopEFvvEJNS_7WeakPtrIS3_EEEEEFvvEE3RunEPNS0_13BindStateBaseE
  #12 0x7f66fa20e941 _ZN4base8internal7InvokerINS0_9BindStateIMN8autofill15AutofillManagerEFvvEJNS_7WeakPtrIS4_EEEEEFvvEE3RunEPNS0_13BindStateBaseE
  #13 0x7f66fd2fdfc9 base::debug::TaskAnnotator::RunTask()
  #14 0x7f66fd28d745 base::MessageLoop::RunTask()
  #15 0x7f66fd28da58 base::MessageLoop::DeferOrRunPendingTask()
  #16 0x7f66fd28dd7b base::MessageLoop::DoWork()
  #17 0x7f66fd28fcda base::(anonymous namespace)::WorkSourceDispatch()
  #18 0x7f66f827dd13 g_main_context_dispatch
  #19 0x7f66f827e060 <unknown>
  #20 0x7f66f827e124 g_main_context_iteration
  #21 0x7f66fd28faa6 base::MessagePumpGlib::Run()
  #22 0x7f66fd28d241 base::MessageLoop::RunHandler()
  #23 0x7f66fd2b06c0 base::RunLoop::Run()
  #24 0x7f66fd152b7a ChromeBrowserMainParts::MainMessageLoopRun()
  #25 0x7f66fa969cd9 content::BrowserMainLoop::RunMainMessageLoopParts()
  #26 0x7f66fa96cfe8 content::BrowserMainRunnerImpl::Run()
  #27 0x7f66fa96586c content::BrowserMain()
  #28 0x7f66fceb48cb content::RunNamedProcessTypeMain()
  #29 0x7f66fceb5343 content::ContentMainRunnerImpl::Run()
  #30 0x7f66fceb3c10 content::ContentMain()
  #31 0x7f66fa1ecf3b ChromeMain
  #32 0x7f66f32547ed __libc_start_main
  #33 0x7f66fa1ece11 <unknown>

This is a recent flaky regression and needs to be diagnosed right away as it forced disabling of an important test. Who can triage it?