On test: https://build.chromium.org/p/chromium.linux/builders/Linux%20Tests%20%28dbg%29%281%29

This is a common style of error:

MediaRouterElementsBrowserTest.MediaRouterElementsTestMediaRouterContainer (run #1):
[ RUN      ] MediaRouterElementsBrowserTest.MediaRouterElementsTestMediaRouterContainer
[1:1:0301/145341:ERROR:memory_mapped_file.cc(40)] Couldn't open /tmp/run55DEJ2/out/Debug/chrome_200_percent.pak
[1:1:0301/145341:ERROR:data_pack.cc(80)] Failed to mmap datapack
Xlib:  extension "RANDR" missing on display ":9".
[20434:20434:0301/145342:ERROR:memory_mapped_file.cc(40)] Couldn't open /tmp/run55DEJ2/out/Debug/chrome_200_percent.pak
[20434:20434:0301/145342:ERROR:data_pack.cc(80)] Failed to mmap datapack
Xlib:  extension "RANDR" missing on display ":9".
[20434:20434:0301/145343:WARNING:password_store_factory.cc(250)] Using basic (unencrypted) store for password storage. See https://chromium.googlesource.com/chromium/src/+/master/docs/linux_password_storage.md for more information about password storage options.
[20434:20434:0301/145353:WARNING:CONSOLE(0)] "::shadow pseudo-element is deprecated. See https://www.chromestatus.com/features/6750456638341120 for more details.", source:  (0)
[20434:20434:0301/145354:INFO:CONSOLE(1180)] "Running TestCase MediaRouterElementsBrowserTest.MediaRouterElementsTestMediaRouterContainer", source: test_api.js (1180)
BrowserTestBase signal handler received SIGTERM. Backtrace:
#0 0x7ff9263e584e base::debug::StackTrace::StackTrace()
#1 0x00000248f43a content::(anonymous namespace)::DumpStackTraceSignalHandler()
#2 0x7ff911c33150 <unknown>
#3 0x7ff911ce49d3 __poll
#4 0x7ff916e71ff6 <unknown>
#5 0x7ff916e72124 g_main_context_iteration
#6 0x7ff92647315f base::MessagePumpGlib::Run()
#7 0x7ff926460b4f base::MessageLoop::RunHandler()
#8 0x7ff9264f21a4 base::RunLoop::Run()
#9 0x000004c9fd83 content::RunThisRunLoop()
#10 0x000004c9fd0a content::RunMessageLoop()
#11 0x00000119ad55 WebUITestHandler::WaitForResult()
#12 0x00000119a9fa WebUITestHandler::RunJavaScriptTestWithResult()
#13 0x000001272fde WebUIBrowserTest::RunJavascriptUsingHandler()
#14 0x000001273324 WebUIBrowserTest::RunJavascriptAsyncTest()
#15 0x000001273257 WebUIBrowserTest::RunJavascriptTestF()
#16 0x0000014edffe MediaRouterElementsBrowserTest_MediaRouterElementsTestMediaRouterContainer_Test::RunTestOnMainThread()
#17 0x000001580615 InProcessBrowserTest::RunTestOnMainThreadLoop()
#18 0x00000248f217 content::BrowserTestBase::ProxyRunTestOnMainThreadLoop()
#19 0x000000843939 _ZN4base8internal15RunnableAdapterIM25RenderViewContextMenuBaseFvvEE3RunIJEEEvPS2_DpOT_
#20 0x0000008c6d59 _ZN4base8internal12InvokeHelperILb0EvNS0_15RunnableAdapterIMNS_7RunLoopEFvvEEEE8MakeItSoIJPS3_EEEvS6_DpOT_
#21 0x000002490405 _ZN4base8internal7InvokerINS_13IndexSequenceIJLm0EEEENS0_9BindStateINS0_15RunnableAdapterIMN7content15BrowserTestBaseEFvvEEEFvPS7_EJSB_EEENS0_12InvokeHelperILb0EvSA_EEFvvEE3RunEPNS0_13BindStateBaseE
#22 0x000000827f2e base::Callback<>::Run()
#23 0x0000016b4949 ChromeBrowserMainParts::PreMainMessageLoopRunImpl()
#24 0x0000016b3457 ChromeBrowserMainParts::PreMainMessageLoopRun()
#25 0x7ff91e5dac9c content::BrowserMainLoop::PreMainMessageLoopRun()
#26 0x7ff91dd3cd89 _ZN4base8internal15RunnableAdapterIMN7content17GpuWatchdogThreadEFvvEE3RunIJEEEvPS3_DpOT_
#27 0x7ff91e5e07c9 _ZN4base8internal12InvokeHelperILb0EiNS0_15RunnableAdapterIMN7content15BrowserMainLoopEFivEEEE8MakeItSoIJPS4_EEEiS7_DpOT_
#28 0x7ff91e5e078d _ZN4base8internal7InvokerINS_13IndexSequenceIJLm0EEEENS0_9BindStateINS0_15RunnableAdapterIMN7content15BrowserMainLoopEFivEEEFiPS7_EJNS0_17UnretainedWrapperIS7_EEEEENS0_12InvokeHelperILb0EiSA_EEFivEE3RunEPNS0_13BindStateBaseE
#29 0x7ff91dd8ffce base::Callback<>::Run()
#30 0x7ff91ef3b1db content::StartupTaskRunner::RunAllTasksNow()
#31 0x7ff91e5d8e05 content::BrowserMainLoop::CreateStartupTasks()
#32 0x7ff91e5e1991 content::BrowserMainRunnerImpl::Initialize()
#33 0x7ff91e5d536d content::BrowserMain()
#34 0x7ff9200ca3d6 content::RunNamedProcessTypeMain()
#35 0x7ff9200cc29d content::ContentMainRunnerImpl::Run()
#36 0x7ff9200c9bb2 content::ContentMain()
#37 0x00000248ef8a content::BrowserTestBase::SetUp()
#38 0x00000157f029 InProcessBrowserTest::SetUp()
#39 0x000000eefa7a _ZN7testing8internal12InvokeHelperIvNSt3tr15tupleIJEEEE12InvokeMethodI14ServiceProcessMS7_FvvEEEvPT_T0_RKS4_
#40 0x0000058c109e testing::internal::HandleExceptionsInMethodIfSupported<>()
#41 0x0000058b6003 testing::Test::Run()
#42 0x0000058b67e8 testing::TestInfo::Run()
#43 0x0000058b6d8a testing::TestCase::Run()
#44 0x0000058bc11c testing::internal::UnitTestImpl::RunAllTests()
#45 0x000000eef06a _ZN7testing8internal12InvokeHelperIbNSt3tr15tupleIJEEEE12InvokeMethodI20MockServiceIPCServerMS7_FbvEEEbPT_T0_RKS4_
#46 0x0000058c270e testing::internal::HandleExceptionsInMethodIfSupported<>()
#47 0x0000058bbdbf testing::UnitTest::Run()
#48 0x0000015b00f1 RUN_ALL_TESTS()
#49 0x0000015af1af base::TestSuite::Run()
#50 0x0000007b5dcc ChromeBrowserTestSuiteRunner::RunTestSuite()
#51 0x000001568ab8 (anonymous namespace)::ChromeTestLauncherDelegate::RunTestSuite()
#52 0x000004c96282 content::LaunchTests()
#53 0x000001568a09 LaunchChromeTests()
#54 0x0000007b5ce8 main
#55 0x7ff911c1e76d __libc_start_main
#56 0x0000007b5bb5 <unknown>