https://codereview.chromium.org/2630773002 is a culprit

[ RUN      ] BrowserCloseManagerWithBackgroundModeBrowserTest/BrowserCloseManagerWithBackgroundModeBrowserTest.CloseAllBrowsersWithBackgroundMode/1
Xlib:  extension "RANDR" missing on display ":99".
Xlib:  extension "RANDR" missing on display ":99".
[11293:11293:0316/213928.090333:WARNING:audio_manager.cc(295)] Multiple instances of AudioManager detected
[11293:11293:0316/213928.090370:WARNING:audio_manager.cc(254)] Multiple instances of AudioManager detected
[11293:11293:0316/213928.147609:WARNING:password_store_factory.cc(247)] 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.
[11293:11293:0316/213928.416295:FATAL:desktop_window_tree_host_x11.cc(836)] Check failed: !is_active || window_mapped_in_server_.
#0 0x000002e5fe57 base::debug::StackTrace::StackTrace()
#1 0x000002e7887b logging::LogMessage::~LogMessage()
#2 0x000003de5765 views::DesktopWindowTreeHostX11::IsActive()
#3 0x000003de291f views::DesktopWindowTreeHostX11::AfterActivationStateChanged()
#4 0x000003de5601 views::DesktopWindowTreeHostX11::Activate()
#5 0x000003dc0902 views::FocusManager::SetFocusedViewWithReason()
#6 0x00000548dac2 OmniboxViewViews::SetFocus()
#7 0x000005487945 LocationBarView::FocusLocation()
#8 0x0000054794a5 BrowserView::SetFocusToLocationBar()
#9 0x0000031923ed (anonymous namespace)::SessionRestoreImpl::RestoreTabsToBrowser()
#10 0x00000319160f (anonymous namespace)::SessionRestoreImpl::ProcessSessionWindowsAndNotify()
#11 0x00000319128a (anonymous namespace)::SessionRestoreImpl::OnGotSession()
#12 0x000002a9beea _ZN4base8internal7InvokerINS0_9BindStateIMN8sessions27PersistentTabRestoreService8DelegateEFvSt6vectorISt10unique_ptrINS3_13SessionWindowESt14default_deleteIS8_EESaISB_EEiEJNS0_17UnretainedWrapperIS5_EEEEEFvSD_iEE3RunEPNS0_13BindStateBaseEOSD_Oi
#13 0x000003198085 SessionService::OnGotSessionCommands()
#14 0x0000031992df _ZN4base8internal12InvokeHelperILb1EvE8MakeItSoIRKM14SessionServiceFvRKNS_8CallbackIFvSt6vectorISt10unique_ptrIN8sessions13SessionWindowESt14default_deleteIS9_EESaISC_EEiELNS0_8CopyModeE1ELNS0_10RepeatModeE1EEES6_IS7_INS8_14SessionCommandESA_ISL_EESaISN_EEERKNS_7WeakPtrIS4_EEJSK_SP_EEEvOT_OT0_DpOT1_
#15 0x000002a8e7e0 sessions::(anonymous namespace)::RunIfNotCanceled()
#16 0x000002a8f960 _ZN4base8internal13FunctorTraitsIPFvRKNS_8CallbackIFbvELNS0_8CopyModeE1ELNS0_10RepeatModeE1EEERKNS2_IFvSt6vectorISt10unique_ptrIN8sessions14SessionCommandESt14default_deleteISC_EESaISF_EEELS4_1ELS5_1EEESH_EvE6InvokeIJS8_SL_SH_EEEvSN_DpOT_
#17 0x000002a8ed52 _ZN4base8internal13FunctorTraitsINS_8CallbackIFvSt6vectorISt10unique_ptrIN8sessions14SessionCommandESt14default_deleteIS6_EESaIS9_EEELNS0_8CopyModeE1ELNS0_10RepeatModeE1EEEvE6InvokeIRKSF_JSB_EEEvOT_DpOT0_
#18 0x000002a8eba6 _ZN4base8internal7InvokerINS0_9BindStateINS_8CallbackIFvSt6vectorISt10unique_ptrIN8sessions14SessionCommandESt14default_deleteIS7_EESaISA_EEELNS0_8CopyModeE1ELNS0_10RepeatModeE1EEEJNS0_13PassedWrapperISC_EEEEEFvvEE7RunImplIRKSG_RKSt5tupleIJSI_EEJLm0EEEEvOT_OT0_NS_13IndexSequenceIJXspT1_EEEE
#19 0x00000176dc20 _ZNO4base8internal8RunMixinINS_8CallbackIFvvELNS0_8CopyModeE0ELNS0_10RepeatModeE0EEEE3RunEv
#20 0x000002f0e0fa base::debug::TaskAnnotator::RunTask()
#21 0x000002e7fe0d base::MessageLoop::RunTask()
#22 0x000002e804b6 base::MessageLoop::DoWork()
#23 0x000002e8269a base::(anonymous namespace)::WorkSourceDispatch()
#24 0x7fa5f32f8e04 g_main_context_dispatch
#25 0x7fa5f32f9048 <unknown>
#26 0x7fa5f32f90ec g_main_context_iteration
#27 0x000002e82476 base::MessagePumpGlib::Run()
#28 0x000002e7fb5e base::MessageLoop::RunHandler()
#29 0x000002ea890c base::RunLoop::Run()
#30 0x0000035847dd content::MessageLoopRunner::Run()
#31 0x000003584e43 content::WindowedNotificationObserver::Wait()
#32 0x000002f3c4f1 ui_test_utils::BrowserAddedObserver::WaitForSingleNewBrowser()
#33 0x000000bf05c9 BrowserCloseManagerWithBackgroundModeBrowserTest_CloseAllBrowsersWithBackgroundMode_Test::RunTestOnMainThread()
#34 0x000002f386af InProcessBrowserTest::RunTestOnMainThreadLoop()
#35 0x000003551276 content::BrowserTestBase::ProxyRunTestOnMainThreadLoop()
#36 0x000003378959 ChromeBrowserMainParts::PreMainMessageLoopRunImpl()
#37 0x000003377811 ChromeBrowserMainParts::PreMainMessageLoopRun()
#38 0x000001ac0985 content::BrowserMainLoop::PreMainMessageLoopRun()
#39 0x000001eb1286 content::StartupTaskRunner::RunAllTasksNow()
#40 0x000001abe81b content::BrowserMainLoop::CreateStartupTasks()
#41 0x000001ac456e content::BrowserMainRunnerImpl::Initialize()
#42 0x000001abbc98 content::BrowserMain()
#43 0x000002e3b613 content::RunNamedProcessTypeMain()
#44 0x000002e3c326 content::ContentMainRunnerImpl::Run()
#45 0x000002e3a924 content::ContentMain()
#46 0x000003550b80 content::BrowserTestBase::SetUp()
#47 0x000002f36cf1 InProcessBrowserTest::SetUp()
#48 0x000003d2550e testing::Test::Run()
#49 0x000003d260d0 testing::TestInfo::Run()
#50 0x000003d26447 testing::TestCase::Run()
#51 0x000003d2d697 testing::internal::UnitTestImpl::RunAllTests()
#52 0x000003d2d317 testing::UnitTest::Run()
#53 0x000002f49e51 base::TestSuite::Run()
#54 0x000002e50368 ChromeTestSuiteRunner::RunTestSuite()
#55 0x00000358067c content::LaunchTests()
#56 0x000002e502e7 main
#57 0x7fa5ed883f45 __libc_start_main
#58 0x000000605531 <unknown>

[1:1:0100/000000.629406:ERROR:broker_posix.cc(41)] Invalid node channel message

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9b35aa2cb18ff78d6cfc843f0e9414ccb6c22150

commit 9b35aa2cb18ff78d6cfc843f0e9414ccb6c22150
Author: thomasanderson <thomasanderson@google.com>
Date: Fri Mar 17 19:45:27 2017

X11: Fix test flakes related to window focus

This CL removes code intended to fix "some tests depending on a window
being IsActive() immediately after an Activate()".  After
https://codereview.chromium.org/2630773002, all of these cases should
be using WidgetActivationWaiter, so this is unnecessary.  This was
causing DCHECK(!is_active || window_mapped_in_server_) to fail.

In addition, XSetInputFocus on an unmapped window will fail, so
supress the error in this case.  This is the same thing GTK does
https://github.com/GNOME/gtk/blob/7ade6e3f4668220f0fa1382944a87e63691ad9ad/gdk/x11/gdkwindow-x11.c#L1904

CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_chromium_dbg_ng
BUG= 701722 , 701921 , 701706 , 701485 , 701484 , 700692 , 700683 , 700661 , 701886 
R=erg@chromium.org

Review-Url: https://codereview.chromium.org/2756183003
Cr-Commit-Position: refs/heads/master@{#457859}

[modify] https://crrev.com/9b35aa2cb18ff78d6cfc843f0e9414ccb6c22150/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc

Detected 3 new flakes for test/step "BrowserCloseManagerWithBackgroundModeBrowserTest/BrowserCloseManagerWithBackgroundModeBrowserTest.CloseAllBrowsersWithBackgroundMode/1". To see the actual flakes, please visit https://chromium-try-flakes.appspot.com/all_flake_occurrences?key=ahVzfmNocm9taXVtLXRyeS1mbGFrZXNykgELEgVGbGFrZSKGAUJyb3dzZXJDbG9zZU1hbmFnZXJXaXRoQmFja2dyb3VuZE1vZGVCcm93c2VyVGVzdC9Ccm93c2VyQ2xvc2VNYW5hZ2VyV2l0aEJhY2tncm91bmRNb2RlQnJvd3NlclRlc3QuQ2xvc2VBbGxCcm93c2Vyc1dpdGhCYWNrZ3JvdW5kTW9kZS8xDA. This message was posted automatically by the chromium-try-flakes app. Since flakiness is ongoing, the issue was moved back into Sheriff Bug Queue (unless already there).

Isn't it already fixed?