Findit identified the culprit r562324 with confidence 70.0% in the config "chromium.memory / Linux TSan Tests"
based on the flakiness trend:

https://findit-for-me.appspot.com/waterfall/flake?key=ag9zfmZpbmRpdC1mb3ItbWVy7wELEhdNYXN0ZXJGbGFrZUFuYWx5c2lzUm9vdCK4AWNocm9taXVtLm1lbW9yeS9MaW51eCBUU2FuIFRlc3RzLzIyMDc2L2NvbnRlbnRfYnJvd3NlcnRlc3RzL1RtRjJhV2RoZEdsdmJrTnZiblJ5YjJ4c1pYSkNjbTkzYzJWeVZHVnpkQzVPWVhacFoyRjBhVzl1Vkhsd1pVTnNZWE56YVdacFkyRjBhVzl1WDA5dU1WTmhiV1ZFYjJOMWJXVnVkRlJ2TVZkb2FXeGxNVkJsYm1ScGJtYz0MCxITTWFzdGVyRmxha2VBbmFseXNpcxgBDA


Automatically posted by the findit-for-me app (https://goo.gl/Ot9f7N).
Feedback is welcome! Please use component Tools>Test>FindIt>Flakiness

I'm unconvinced that the CL in #1 is the culprit.

khushalsagar@: Could you confirm?

This is hitting a data race in ResourceDispatcherHostImpl, which looks very unrelated to any of the code being touched in that change. Here is the stack:

WARNING: ThreadSanitizer: data race (pid=27580)
  Write of size 8 at 0x7b4400002b28 by main thread:
    #0 content::ResourceDispatcherHostImpl::SetDelegate(content::ResourceDispatcherHostDelegate*) content/browser/loader/resource_dispatcher_host_impl.cc:372:13 (content_browsertests+0x4356f11)
    #1 content::(anonymous namespace)::DoReplaceStateWhilePending(content::Shell*, GURL const&, GURL const&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&) content/browser/frame_host/navigation_controller_impl_browsertest.cc:4989:34 (content_browsertests+0x1b81608)
    #2 content::NavigationControllerBrowserTest_NavigationTypeClassification_On1SameDocumentTo1While1Pending_Test::RunTestOnMainThread() content/browser/frame_host/navigation_controller_impl_browsertest.cc:5027:3 (content_browsertests+0x1b819d9)
    #3 content::BrowserTestBase::ProxyRunTestOnMainThreadLoop() content/public/test/browser_test_base.cc:385:5 (content_browsertests+0x4a3d852)
    #4 Invoke<void (content::BrowserTestBase::*)(), content::BrowserTestBase *> base/bind_internal.h:447:12 (content_browsertests+0x4a3e818)
    #5 MakeItSo<void (content::BrowserTestBase::*const &)(), content::BrowserTestBase *> base/bind_internal.h:547 (content_browsertests+0x4a3e818)
    #6 RunImpl<void (content::BrowserTestBase::*const &)(), const std::__1::tuple<base::internal::UnretainedWrapper<content::BrowserTestBase> > &, 0> base/bind_internal.h:621 (content_browsertests+0x4a3e818)
    #7 base::internal::Invoker<base::internal::BindState<void (content::BrowserTestBase::*)(), base::internal::UnretainedWrapper<content::BrowserTestBase> >, void ()>::Run(base::internal::BindStateBase*) base/bind_internal.h:603 (content_browsertests+0x4a3e818)
    #8 Run base/callback.h:125:12 (content_browsertests+0x4b1d680)
    #9 content::ShellBrowserMainParts::PreMainMessageLoopRun() content/shell/browser/shell_browser_main_parts.cc:203 (content_browsertests+0x4b1d680)
    #10 content::BrowserMainLoop::PreMainMessageLoopRun() content/browser/browser_main_loop.cc:961:13 (content_browsertests+0x4036bc0)
    #11 Invoke<int (content::BrowserMainLoop::*)(), content::BrowserMainLoop *> base/bind_internal.h:447:12 (content_browsertests+0x4039d18)
    #12 MakeItSo<int (content::BrowserMainLoop::*const &)(), content::BrowserMainLoop *> base/bind_internal.h:547 (content_browsertests+0x4039d18)
    #13 RunImpl<int (content::BrowserMainLoop::*const &)(), const std::__1::tuple<base::internal::UnretainedWrapper<content::BrowserMainLoop> > &, 0> base/bind_internal.h:621 (content_browsertests+0x4039d18)
    #14 base::internal::Invoker<base::internal::BindState<int (content::BrowserMainLoop::*)(), base::internal::UnretainedWrapper<content::BrowserMainLoop> >, int ()>::Run(base::internal::BindStateBase*) base/bind_internal.h:603 (content_browsertests+0x4039d18)
    #15 Run base/callback.h:125:12 (content_browsertests+0x4612b6e)
    #16 content::StartupTaskRunner::RunAllTasksNow() content/browser/startup_task_runner.cc:44 (content_browsertests+0x4612b6e)
    #17 content::BrowserMainLoop::CreateStartupTasks() content/browser/browser_main_loop.cc:872:25 (content_browsertests+0x4034ebd)
    #18 content::BrowserMainRunnerImpl::Initialize(content::MainFunctionParams const&, std::__1::unique_ptr<content::BrowserProcessSubThread, std::__1::default_delete<content::BrowserProcessSubThread> >) content/browser/browser_main_runner_impl.cc:148:15 (content_browsertests+0x403a2f1)
    #19 content::BrowserMainRunnerImpl::Initialize(content::MainFunctionParams const&) content/browser/browser_main_runner_impl.cc:66:10 (content_browsertests+0x403a210)
    #20 ShellBrowserMain(content::MainFunctionParams const&, std::__1::unique_ptr<content::BrowserMainRunner, std::__1::default_delete<content::BrowserMainRunner> > const&) content/shell/browser/shell_browser_main.cc:22:32 (content_browsertests+0x4b1cc97)
    #21 content::ShellMainDelegate::RunProcess(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, content::MainFunctionParams const&) content/shell/app/shell_main_delegate.cc:344:16 (content_browsertests+0x4ab27e2)
    #22 RunBrowserProcessMain content/app/content_main_runner_impl.cc:606:31 (content_browsertests+0x3ee832e)
    #23 content::ContentMainRunnerImpl::Run() content/app/content_main_runner_impl.cc:964 (content_browsertests+0x3ee832e)
    #24 content::ContentServiceManagerMainDelegate::RunEmbedderProcess() content/app/content_service_manager_main_delegate.cc:53:32 (content_browsertests+0x303277f)
    #25 service_manager::Main(service_manager::MainParams const&) services/service_manager/embedder/main.cc:459:29 (content_browsertests+0x6b6ac42)
    #26 content::ContentMain(content::ContentMainParams const&) content/app/content_main.cc:19:10 (content_browsertests+0x3032f2e)
    #27 content::BrowserTestBase::SetUp() content/public/test/browser_test_base.cc:323:3 (content_browsertests+0x4a3d335)
    #28 content::ContentBrowserTest::SetUp() content/public/test/content_browser_test.cc:100:20 (content_browsertests+0x4a2d09b)
    #29 testing::Test::Run() third_party/googletest/src/googletest/src/gtest.cc (content_browsertests+0x2c3555b)
    #30 testing::TestInfo::Run() third_party/googletest/src/googletest/src/gtest.cc:2667:11 (content_browsertests+0x2c367bc)
    #31 testing::TestCase::Run() third_party/googletest/src/googletest/src/gtest.cc:2785:28 (content_browsertests+0x2c37046)
    #32 testing::internal::UnitTestImpl::RunAllTests() third_party/googletest/src/googletest/src/gtest.cc:5047:43 (content_browsertests+0x2c475e6)
    #33 testing::UnitTest::Run() third_party/googletest/src/googletest/src/gtest.cc (content_browsertests+0x2c46eca)
    #34 RUN_ALL_TESTS third_party/googletest/src/googletest/include/gtest/gtest.h:2329:46 (content_browsertests+0x4a87be5)
    #35 base::TestSuite::Run() base/test/test_suite.cc:275 (content_browsertests+0x4a87be5)
    #36 content::ContentTestLauncherDelegate::RunTestSuite(int, char**) content/test/content_test_launcher.cc:108:48 (content_browsertests+0x4a32b2b)
    #37 content::LaunchTests(content::TestLauncherDelegate*, unsigned long, int, char**) content/public/test/test_launcher.cc:625:31 (content_browsertests+0x4a63e3c)
    #38 main content/test/content_test_launcher.cc:138:10 (content_browsertests+0x4a32abd)

  Previous read of size 8 at 0x7b4400002b28 by thread T13:
    #0 content::ResourceDispatcherHostImpl::AddStandardHandlers(net::URLRequest*, content::ResourceType, content::ResourceContext*, network::mojom::FetchRequestMode, content::RequestContextType, content::AppCacheService*, int, int, std::__1::unique_ptr<content::ResourceHandler, std::__1::default_delete<content::ResourceHandler> >) content/browser/loader/resource_dispatcher_host_impl.cc:1179:7 (content_browsertests+0x435d125)
    #1 content::ResourceDispatcherHostImpl::BeginNavigationRequest(content::ResourceContext*, net::URLRequestContext*, storage::FileSystemContext*, content::NavigationRequestInfo const&, std::__1::unique_ptr<content::NavigationUIData, std::__1::default_delete<content::NavigationUIData> >, mojo::InterfacePtr<network::mojom::URLLoaderClient>, mojo::InterfaceRequest<network::mojom::URLLoader>, content::ServiceWorkerNavigationHandleCore*, content::AppCacheNavigationHandleCore*, unsigned int, content::GlobalRequestID*) content/browser/loader/resource_dispatcher_host_impl.cc:1738:13 (content_browsertests+0x4360932)
    #2 content::NavigationURLLoaderImpl::URLLoaderRequestController::CreateNonNetworkServiceURLLoader(net::URLRequestContextGetter*, storage::FileSystemContext*, std::__1::unique_ptr<content::NavigationRequestInfo, std::__1::default_delete<content::NavigationRequestInfo> >, content::ServiceWorkerNavigationHandleCore*, content::AppCacheNavigationHandleCore*, mojo::InterfaceRequest<network::mojom::URLLoader>, mojo::InterfacePtr<network::mojom::URLLoaderClient>) content/browser/loader/navigation_url_loader_impl.cc:413:42 (content_browsertests+0x434a371)
    #3 void base::internal::FunctorTraits<void (content::NavigationURLLoaderImpl::URLLoaderRequestController::*)(net::URLRequestContextGetter*, storage::FileSystemContext*, std::__1::unique_ptr<content::NavigationRequestInfo, std::__1::default_delete<content::NavigationRequestInfo> >, content::ServiceWorkerNavigationHandleCore*, content::AppCacheNavigationHandleCore*, mojo::InterfaceRequest<network::mojom::URLLoader>, mojo::InterfacePtr<network::mojom::URLLoaderClient>), void>::Invoke<void (content::NavigationURLLoaderImpl::URLLoaderRequestController::*)(net::URLRequestContextGetter*, storage::FileSystemContext*, std::__1::unique_ptr<content::NavigationRequestInfo, std::__1::default_delete<content::NavigationRequestInfo> >, content::ServiceWorkerNavigationHandleCore*, content::AppCacheNavigationHandleCore*, mojo::InterfaceRequest<network::mojom::URLLoader>, mojo::InterfacePtr<network::mojom::URLLoaderClient>), base::WeakPtr<content::NavigationURLLoaderImpl::URLLoaderRequestController>, net::URLRequestContextGetter*, storage::FileSystemContext*, std::__1::unique_ptr<content::NavigationRequestInfo, std::__1::default_delete<content::NavigationRequestInfo> >, content::ServiceWorkerNavigationHandleCore*, content::AppCacheNavigationHandleCore*, mojo::InterfaceRequest<network::mojom::URLLoader>, mojo::InterfacePtr<network::mojom::URLLoaderClient> >(void (content::NavigationURLLoaderImpl::URLLoaderRequestController::*)(net::URLRequestContextGetter*, storage::FileSystemContext*, std::__1::unique_ptr<content::NavigationRequestInfo, std::__1::default_delete<content::NavigationRequestInfo> >, content::ServiceWorkerNavigationHandleCore*, content::AppCacheNavigationHandleCore*, mojo::InterfaceRequest<network::mojom::URLLoader>, mojo::InterfacePtr<network::mojom::URLLoaderClient>), base::WeakPtr<content::NavigationURLLoaderImpl::URLLoaderRequestController>&&, net::URLRequestContextGetter*&&, storage::FileSystemContext*&&, std::__1::unique_ptr<content::NavigationRequestInfo, std::__1::default_delete<content::NavigationRequestInfo> >&&, content::ServiceWorkerNavigationHandleCore*&&, content::AppCacheNavigationHandleCore*&&, mojo::InterfaceRequest<network::mojom::URLLoader>&&, mojo::InterfacePtr<network::mojom::URLLoaderClient>&&) base/bind_internal.h:447:12 (content_browsertests+0x434a732)
    #4 MakeItSo<void (content::NavigationURLLoaderImpl::URLLoaderRequestController::*)(net::URLRequestContextGetter *, storage::FileSystemContext *, std::__1::unique_ptr<content::NavigationRequestInfo, std::__1::default_delete<content::NavigationRequestInfo> >, content::ServiceWorkerNavigationHandleCore *, content::AppCacheNavigationHandleCore *, mojo::InterfaceRequest<network::mojom::URLLoader>, mojo::InterfacePtr<network::mojom::URLLoaderClient>), base::WeakPtr<content::NavigationURLLoaderImpl::URLLoaderRequestController>, net::URLRequestContextGetter *, storage::FileSystemContext *, std::__1::unique_ptr<content::NavigationRequestInfo, std::__1::default_delete<content::NavigationRequestInfo> >, content::ServiceWorkerNavigationHandleCore *, content::AppCacheNavigationHandleCore *, mojo::InterfaceRequest<network::mojom::URLLoader>, mojo::InterfacePtr<network::mojom::URLLoaderClient> > base/bind_internal.h:567:5 (content_browsertests+0x434a5a7)
    #5 RunImpl<void (content::NavigationURLLoaderImpl::URLLoaderRequestController::*)(net::URLRequestContextGetter *, storage::FileSystemContext *, std::__1::unique_ptr<content::NavigationRequestInfo, std::__1::default_delete<content::NavigationRequestInfo> >, content::ServiceWorkerNavigationHandleCore *, content::AppCacheNavigationHandleCore *, mojo::InterfaceRequest<network::mojom::URLLoader>, mojo::InterfacePtr<network::mojom::URLLoaderClient>), std::__1::tuple<base::WeakPtr<content::NavigationURLLoaderImpl::URLLoaderRequestController>, base::internal::UnretainedWrapper<net::URLRequestContextGetter>, base::internal::UnretainedWrapper<storage::FileSystemContext>, std::__1::unique_ptr<content::NavigationRequestInfo, std::__1::default_delete<content::NavigationRequestInfo> >, base::internal::UnretainedWrapper<content::ServiceWorkerNavigationHandleCore>, base::internal::UnretainedWrapper<content::AppCacheNavigationHandleCore> >, 0, 1, 2, 3, 4, 5> base/bind_internal.h:621 (content_browsertests+0x434a5a7)
    #6 base::internal::Invoker<base::internal::BindState<void (content::NavigationURLLoaderImpl::URLLoaderRequestController::*)(net::URLRequestContextGetter*, storage::FileSystemContext*, std::__1::unique_ptr<content::NavigationRequestInfo, std::__1::default_delete<content::NavigationRequestInfo> >, content::ServiceWorkerNavigationHandleCore*, content::AppCacheNavigationHandleCore*, mojo::InterfaceRequest<network::mojom::URLLoader>, mojo::InterfacePtr<network::mojom::URLLoaderClient>), base::WeakPtr<content::NavigationURLLoaderImpl::URLLoaderRequestController>, base::internal::UnretainedWrapper<net::URLRequestContextGetter>, base::internal::UnretainedWrapper<storage::FileSystemContext>, std::__1::unique_ptr<content::NavigationRequestInfo, std::__1::default_delete<content::NavigationRequestInfo> >, base::internal::UnretainedWrapper<content::ServiceWorkerNavigationHandleCore>, base::internal::UnretainedWrapper<content::AppCacheNavigationHandleCore> >, void (mojo::InterfaceRequest<network::mojom::URLLoader>, mojo::InterfacePtr<network::mojom::URLLoaderClient>)>::RunOnce(base::internal::BindStateBase*, mojo::InterfaceRequest<network::mojom::URLLoader>&&, mojo::InterfacePtr<network::mojom::URLLoaderClient>&&) base/bind_internal.h:589 (content_browsertests+0x434a5a7)
    #7 Run base/callback.h:96:12 (content_browsertests+0x2cef500)
    #8 content::SingleRequestURLLoaderFactory::HandlerState::HandleRequest(mojo::InterfaceRequest<network::mojom::URLLoader>, mojo::InterfacePtr<network::mojom::URLLoaderClient>) content/common/single_request_url_loader_factory.cc:36 (content_browsertests+0x2cef500)
    #9 content::SingleRequestURLLoaderFactory::CreateLoaderAndStart(mojo::InterfaceRequest<network::mojom::URLLoader>, int, int, unsigned int, network::ResourceRequest const&, mojo::InterfacePtr<network::mojom::URLLoaderClient>, net::MutableNetworkTrafficAnnotationTag const&) content/common/single_request_url_loader_factory.cc:88:11 (content_browsertests+0x2cef3c1)
    #10 content::ThrottlingURLLoader::StartNow(network::SharedURLLoaderFactory*, int, int, unsigned int, network::ResourceRequest*, scoped_refptr<base::SingleThreadTaskRunner>) content/common/throttling_url_loader.cc:269:12 (content_browsertests+0x2cf1d7b)
    #11 content::ThrottlingURLLoader::Start(scoped_refptr<network::SharedURLLoaderFactory>, int, int, unsigned int, network::ResourceRequest*, scoped_refptr<base::SingleThreadTaskRunner>) content/common/throttling_url_loader.cc:252:3 (content_browsertests+0x2cf0757)
    #12 content::ThrottlingURLLoader::CreateLoaderAndStart(scoped_refptr<network::SharedURLLoaderFactory>, std::__1::vector<std::__1::unique_ptr<content::URLLoaderThrottle, std::__1::default_delete<content::URLLoaderThrottle> >, std::__1::allocator<std::__1::unique_ptr<content::URLLoaderThrottle, std::__1::default_delete<content::URLLoaderThrottle> > > >, int, int, unsigned int, network::ResourceRequest*, network::mojom::URLLoaderClient*, net::NetworkTrafficAnnotationTag const&, scoped_refptr<base::SingleThreadTaskRunner>) content/common/throttling_url_loader.cc:162:11 (content_browsertests+0x2cf02a5)
    #13 content::NavigationURLLoaderImpl::URLLoaderRequestController::StartWithoutNetworkService(net::URLRequestContextGetter*, storage::FileSystemContext*, content::ServiceWorkerNavigationHandleCore*, content::AppCacheNavigationHandleCore*, std::__1::unique_ptr<content::NavigationRequestInfo, std::__1::default_delete<content::NavigationRequestInfo> >, std::__1::unique_ptr<content::NavigationUIData, std::__1::default_delete<content::NavigationUIData> >) content/browser/loader/navigation_url_loader_impl.cc:463:21 (content_browsertests+0x43475ef)
    #14 Invoke<void (content::NavigationURLLoaderImpl::URLLoaderRequestController::*)(net::URLRequestContextGetter *, storage::FileSystemContext *, content::ServiceWorkerNavigationHandleCore *, content::AppCacheNavigationHandleCore *, std::__1::unique_ptr<content::NavigationRequestInfo, std::__1::default_delete<content::NavigationRequestInfo> >, std::__1::unique_ptr<content::NavigationUIData, std::__1::default_delete<content::NavigationUIData> >), content::NavigationURLLoaderImpl::URLLoaderRequestController *, net::URLRequestContextGetter *, storage::FileSystemContext *, content::ServiceWorkerNavigationHandleCore *, content::AppCacheNavigationHandleCore *, std::__1::unique_ptr<content::NavigationRequestInfo, std::__1::default_delete<content::NavigationRequestInfo> >, std::__1::unique_ptr<content::NavigationUIData, std::__1::default_delete<content::NavigationUIData> > > base/bind_internal.h:447:12 (content_browsertests+0x4350065)
    #15 MakeItSo<void (content::NavigationURLLoaderImpl::URLLoaderRequestController::*)(net::URLRequestContextGetter *, storage::FileSystemContext *, content::ServiceWorkerNavigationHandleCore *, content::AppCacheNavigationHandleCore *, std::__1::unique_ptr<content::NavigationRequestInfo, std::__1::default_delete<content::NavigationRequestInfo> >, std::__1::unique_ptr<content::NavigationUIData, std::__1::default_delete<content::NavigationUIData> >), content::NavigationURLLoaderImpl::URLLoaderRequestController *, net::URLRequestContextGetter *, storage::FileSystemContext *, content::ServiceWorkerNavigationHandleCore *, content::AppCacheNavigationHandleCore *, std::__1::unique_ptr<content::NavigationRequestInfo, std::__1::default_delete<content::NavigationRequestInfo> >, std::__1::unique_ptr<content::NavigationUIData, std::__1::default_delete<content::NavigationUIData> > > base/bind_internal.h:547 (content_browsertests+0x4350065)
    #16 RunImpl<void (content::NavigationURLLoaderImpl::URLLoaderRequestController::*)(net::URLRequestContextGetter *, storage::FileSystemContext *, content::ServiceWorkerNavigationHandleCore *, content::AppCacheNavigationHandleCore *, std::__1::unique_ptr<content::NavigationRequestInfo, std::__1::default_delete<content::NavigationRequestInfo> >, std::__1::unique_ptr<content::NavigationUIData, std::__1::default_delete<content::NavigationUIData> >), std::__1::tuple<base::internal::UnretainedWrapper<content::NavigationURLLoaderImpl::URLLoaderRequestController>, base::internal::RetainedRefWrapper<net::URLRequestContextGetter>, base::internal::UnretainedWrapper<storage::FileSystemContext>, base::internal::UnretainedWrapper<content::ServiceWorkerNavigationHandleCore>, base::internal::UnretainedWrapper<content::AppCacheNavigationHandleCore>, std::__1::unique_ptr<content::NavigationRequestInfo, std::__1::default_delete<content::NavigationRequestInfo> >, std::__1::unique_ptr<content::NavigationUIData, std::__1::default_delete<content::NavigationUIData> > >, 0, 1, 2, 3, 4, 5, 6> base/bind_internal.h:621 (content_browsertests+0x4350065)
    #17 base::internal::Invoker<base::internal::BindState<void (content::NavigationURLLoaderImpl::URLLoaderRequestController::*)(net::URLRequestContextGetter*, storage::FileSystemContext*, content::ServiceWorkerNavigationHandleCore*, content::AppCacheNavigationHandleCore*, std::__1::unique_ptr<content::NavigationRequestInfo, std::__1::default_delete<content::NavigationRequestInfo> >, std::__1::unique_ptr<content::NavigationUIData, std::__1::default_delete<content::NavigationUIData> >), base::internal::UnretainedWrapper<content::NavigationURLLoaderImpl::URLLoaderRequestController>, base::internal::RetainedRefWrapper<net::URLRequestContextGetter>, base::internal::UnretainedWrapper<storage::FileSystemContext>, base::internal::UnretainedWrapper<content::ServiceWorkerNavigationHandleCore>, base::internal::UnretainedWrapper<content::AppCacheNavigationHandleCore>, std::__1::unique_ptr<content::NavigationRequestInfo, std::__1::default_delete<content::NavigationRequestInfo> >, std::__1::unique_ptr<content::NavigationUIData, std::__1::default_delete<content::NavigationUIData> > >, void ()>::RunOnce(base::internal::BindStateBase*) base/bind_internal.h:589 (content_browsertests+0x4350065)
    #18 Run base/callback.h:96:12 (content_browsertests+0x4edbc3a)
    #19 base::debug::TaskAnnotator::RunTask(char const*, base::PendingTask*) base/debug/task_annotator.cc:101 (content_browsertests+0x4edbc3a)
    #20 base::internal::IncomingTaskQueue::RunTask(base::PendingTask*) base/message_loop/incoming_task_queue.cc:124:19 (content_browsertests+0x4f0ae4b)
    #21 base::MessageLoop::RunTask(base::PendingTask*) base/message_loop/message_loop.cc:319:25 (content_browsertests+0x4f0943d)
    #22 DeferOrRunPendingTask base/message_loop/message_loop.cc:329:5 (content_browsertests+0x4f09b00)
    #23 base::MessageLoop::DoWork() base/message_loop/message_loop.cc:373 (content_browsertests+0x4f09b00)
    #24 base::MessagePumpLibevent::Run(base::MessagePump::Delegate*) base/message_loop/message_pump_libevent.cc:210:31 (content_browsertests+0x4fd45d4)
    #25 Run base/message_loop/message_loop.cc:271:12 (content_browsertests+0x4f08e60)
    #26 non-virtual thunk to base::MessageLoop::Run(bool) base/message_loop/message_loop.cc (content_browsertests+0x4f08e60)
    #27 base::RunLoop::Run() base/run_loop.cc:102:14 (content_browsertests+0x4f39cfa)
    #28 base::Thread::Run(base::RunLoop*) base/threading/thread.cc:255:13 (content_browsertests+0x4f7df19)
    #29 content::BrowserProcessSubThread::IOThreadRun(base::RunLoop*) content/browser/browser_process_sub_thread.cc:178:11 (content_browsertests+0x4044936)
    #30 content::BrowserProcessSubThread::Run(base::RunLoop*) content/browser/browser_process_sub_thread.cc:128:7 (content_browsertests+0x4044898)
    #31 base::Thread::ThreadMain() base/threading/thread.cc:337:3 (content_browsertests+0x4f7e17c)
    #32 base::(anonymous namespace)::ThreadFunc(void*) base/threading/platform_thread_posix.cc:76:13 (content_browsertests+0x4fd011d)

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/12a47bfd6840c4f9cd7c59bcc3e9683718efbf53

commit 12a47bfd6840c4f9cd7c59bcc3e9683718efbf53
Author: Adithya Srinivasan <adithyas@chromium.org>
Date: Tue May 29 16:22:21 2018

Disable NavigationControllerBrowserTest.NavigationTypeClassification_On1SameDocumentTo1While1Pending on Tsan

Bug:  847326 
Change-Id: I52eb69c9cff27ff01b4f7583a2457d5e3bdd1205
Tbr: avi@chromium.org
Reviewed-on: https://chromium-review.googlesource.com/1076319
Reviewed-by: Adithya Srinivasan <adithyas@chromium.org>
Commit-Queue: Adithya Srinivasan <adithyas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#562453}
[modify] https://crrev.com/12a47bfd6840c4f9cd7c59bcc3e9683718efbf53/content/browser/frame_host/navigation_controller_impl_browsertest.cc

I couldn't really find a culprit, so I'm assigning this to the test owner.

This is a race between content::ResourceDispatcherHostImpl::AddStandardHandlers and the use of NavigationStallDelegate.

NavigationStallDelegate has a comment:
// Note: This class likely doesn't work with PlzNavigate.
// TODO(nasko): Reimplement this class using NavigationThrottle, once it has
// the ability to defer navigation requests.

As PlzNavigate is enabled, we should move NavigationStallDelegate to be a NavigationThrottle.

 Issue 850045  has been merged into this issue.

Note that NavigationControllerBrowserTest.NavigationTypeClassification_On1SameDocumentToXWhile2Pending behaves the same way. TSan is also reporting races involving delete() (see https://logs.chromium.org/v/?s=chromium%2Fbuildbucket%2Fcr-buildbucket.appspot.com%2F8944462701668877232%2F%2B%2Fsteps%2Fcontent_browsertests%2F0%2Fstdout), which may potentially lead to test crashes on non-TSan builders.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3fb2b187cd72f3bbbde7b1282a796df6e0877dc4

commit 3fb2b187cd72f3bbbde7b1282a796df6e0877dc4
Author: Alexander Potapenko <glider@google.com>
Date: Wed Jun 06 15:19:49 2018

Unconditionally disable racy NavigationControllerBrowserTest tests.

TSan error reports involve destruction stacks, which means the same tests
may crash on other builders.

TBR=nasko@chromium.org

Bug:  847326 
Change-Id: Ibac5d6eb25232ece33029eea2a563ab72a6d79f1
Reviewed-on: https://chromium-review.googlesource.com/1088915
Commit-Queue: Alexander Potapenko <glider@chromium.org>
Reviewed-by: Alexander Potapenko <glider@chromium.org>
Cr-Commit-Position: refs/heads/master@{#564895}
[modify] https://crrev.com/3fb2b187cd72f3bbbde7b1282a796df6e0877dc4/content/browser/frame_host/navigation_controller_impl_browsertest.cc

I don't have the bandwidth to work on this right now, so I'm marking it as available for anyone to pick up.

This might be the root cause of a ton of flaky navigation tests lately.  Any navigation folks available to work on this?

Another test that's affected is NavigationControllerBrowserTest.NavigationTypeClassification_On1SameDocumentToXWhile1Pending

I finally have a few cycles to look at this. Assigning to myself.

I have a CL removing NavigationStallDelegate and replacing its last usage by TestNavigationManager at https://chromium-review.googlesource.com/c/chromium/src/+/1213263.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0ffcb7d2e89870677a3de98c626639259a20433b

commit 0ffcb7d2e89870677a3de98c626639259a20433b
Author: clamy <clamy@chromium.org>
Date: Mon Sep 17 13:24:24 2018

Remove NavigationStallDelegate

This test helper class is outdated and has been replaced by
TestNavigationManager. This CL removes, rewrites the tests that were
still using it and re-enables some of those tests that were flaky due to
a race between NavigationStallDelegate and

ResourceDispatcherHostImpl: :AddStandardHandlers.
Bug:  847326 
Change-Id: I2acd9f3dde13433583e3c8863dfb2cecd11fc9c7
Reviewed-on: https://chromium-review.googlesource.com/1213263
Commit-Queue: Camille Lamy <clamy@chromium.org>
Reviewed-by: Nasko Oskov <nasko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#591656}
[modify] https://crrev.com/0ffcb7d2e89870677a3de98c626639259a20433b/content/browser/frame_host/navigation_controller_impl_browsertest.cc
[modify] https://crrev.com/0ffcb7d2e89870677a3de98c626639259a20433b/content/browser/frame_host/render_frame_host_manager_browsertest.cc
[modify] https://crrev.com/0ffcb7d2e89870677a3de98c626639259a20433b/content/browser/site_per_process_browsertest.cc
[modify] https://crrev.com/0ffcb7d2e89870677a3de98c626639259a20433b/content/browser/web_contents/web_contents_impl_browsertest.cc
[modify] https://crrev.com/0ffcb7d2e89870677a3de98c626639259a20433b/content/test/content_browser_test_utils_internal.cc
[modify] https://crrev.com/0ffcb7d2e89870677a3de98c626639259a20433b/content/test/content_browser_test_utils_internal.h