I'm trying to add viz_browser_tests to the memory bots. The msan tryjob has oodles of failures:

https://ci.chromium.org/p/chromium/builders/luci.chromium.try/linux_chromium_msan_rel_ng/1093

I clicked 3 tests at random and they all had the same stack, so maybe it's not that many uninitialized variables:

[ RUN      ] WebRtcRtpBrowserTest.GetSenders
Xlib:  extension "RANDR" missing on display ":99".
[24454:24509:0606/132251.066072:ERROR:bus.cc(394)] Failed to connect to the bus: Could not parse server address: Unknown address type (examples of valid types are "tcp" and on UNIX "unix")
[24454:24454:0606/132251.160312: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.
(browser_tests:24454): LIBDBUSMENU-GLIB-WARNING **: Unable to get session bus: Unknown or unsupported transport 'disabled' for address 'disabled:'
==24454==WARNING: MemorySanitizer: use-of-uninitialized-value
    #0 0x15106b06 in void std::__1::__sift_up<net::PrioritizedTaskRunner::JobComparer&, std::__1::__wrap_iter<net::PrioritizedTaskRunner::Job*> >(std::__1::__wrap_iter<net::PrioritizedTaskRunner::Job*>, std::__1::__wrap_iter<net::PrioritizedTaskRunner::Job*>, net::PrioritizedTaskRunner::JobComparer&, std::__1::iterator_traits<std::__1::__wrap_iter<net::PrioritizedTaskRunner::Job*> >::difference_type) ./../../buildtools/third_party/libc++/trunk/include/algorithm:4889:13
    #1 0x151036d8 in push_heap<std::__1::__wrap_iter<net::PrioritizedTaskRunner::Job *>, net::PrioritizedTaskRunner::JobComparer> ./../../buildtools/third_party/libc++/trunk/include/algorithm:4917:5
    #2 0x151036d8 in net::PrioritizedTaskRunner::PostTaskAndReply(base::Location const&, base::OnceCallback<void ()>, base::OnceCallback<void ()>, unsigned int) ./../../net/base/prioritized_task_runner.cc:44:0
    #3 0x1511969a in disk_cache::SimpleEntryImpl::WriteDataInternal(int, int, net::IOBuffer*, int, base::RepeatingCallback<void (int)> const&, bool) ./../../net/disk_cache/simple/simple_entry_impl.cc:1056:29
    #4 0x15109bb3 in disk_cache::SimpleEntryImpl::RunNextOperationIfNeeded() ./../../net/disk_cache/simple/simple_entry_impl.cc:676:9
    #5 0x15123305 in disk_cache::SimpleEntryImpl::EntryOperationComplete(base::RepeatingCallback<void (int)> const&, disk_cache::SimpleEntryStat const&, int) ./../../net/disk_cache/simple/simple_entry_impl.cc:1352:3
    #6 0x15121311 in disk_cache::SimpleEntryImpl::WriteOperationComplete(int, base::RepeatingCallback<void (int)> const&, std::__1::unique_ptr<disk_cache::SimpleEntryStat, std::__1::default_delete<disk_cache::SimpleEntryStat> >, std::__1::unique_ptr<disk_cache::SimpleSynchronousEntry::WriteResult, std::__1::default_delete<disk_cache::SimpleSynchronousEntry::WriteResult> >, net::IOBuffer*) ./../../net/disk_cache/simple/simple_entry_impl.cc:1424:3
    #7 0x15128e66 in Invoke<void (disk_cache::SimpleEntryImpl::*)(int, const base::RepeatingCallback<void (int)> &, std::__1::unique_ptr<disk_cache::SimpleEntryStat, std::__1::default_delete<disk_cache::SimpleEntryStat> >, std::__1::unique_ptr<disk_cache::SimpleSynchronousEntry::WriteResult, std::__1::default_delete<disk_cache::SimpleSynchronousEntry::WriteResult> >, net::IOBuffer *), const scoped_refptr<disk_cache::SimpleEntryImpl> &, const int &, const base::RepeatingCallback<void (int)> &, std::__1::unique_ptr<disk_cache::SimpleEntryStat, std::__1::default_delete<disk_cache::SimpleEntryStat> >, std::__1::unique_ptr<disk_cache::SimpleSynchronousEntry::WriteResult, std::__1::default_delete<disk_cache::SimpleSynchronousEntry::WriteResult> >, net::IOBuffer *> ./../../base/bind_internal.h:507:12
    #8 0x15128e66 in MakeItSo<void (disk_cache::SimpleEntryImpl::*const &)(int, const base::RepeatingCallback<void (int)> &, std::__1::unique_ptr<disk_cache::SimpleEntryStat, std::__1::default_delete<disk_cache::SimpleEntryStat> >, std::__1::unique_ptr<disk_cache::SimpleSynchronousEntry::WriteResult, std::__1::default_delete<disk_cache::SimpleSynchronousEntry::WriteResult> >, net::IOBuffer *), const scoped_refptr<disk_cache::SimpleEntryImpl> &, const int &, const base::RepeatingCallback<void (int)> &, std::__1::unique_ptr<disk_cache::SimpleEntryStat, std::__1::default_delete<disk_cache::SimpleEntryStat> >, std::__1::unique_ptr<disk_cache::SimpleSynchronousEntry::WriteResult, std::__1::default_delete<disk_cache::SimpleSynchronousEntry::WriteResult> >, net::IOBuffer *> ./../../base/bind_internal.h:607:0
    #9 0x15128e66 in void base::internal::Invoker<base::internal::BindState<void (disk_cache::SimpleEntryImpl::*)(int, base::RepeatingCallback<void (int)> const&, std::__1::unique_ptr<disk_cache::SimpleEntryStat, std::__1::default_delete<disk_cache::SimpleEntryStat> >, std::__1::unique_ptr<disk_cache::SimpleSynchronousEntry::WriteResult, std::__1::default_delete<disk_cache::SimpleSynchronousEntry::WriteResult> >, net::IOBuffer*), scoped_refptr<disk_cache::SimpleEntryImpl>, int, base::RepeatingCallback<void (int)>, base::internal::PassedWrapper<std::__1::unique_ptr<disk_cache::SimpleEntryStat, std::__1::default_delete<disk_cache::SimpleEntryStat> > >, base::internal::PassedWrapper<std::__1::unique_ptr<disk_cache::SimpleSynchronousEntry::WriteResult, std::__1::default_delete<disk_cache::SimpleSynchronousEntry::WriteResult> > >, base::internal::RetainedRefWrapper<net::IOBuffer> >, void ()>::RunImpl<void (disk_cache::SimpleEntryImpl::* const&)(int, base::RepeatingCallback<void (int)> const&, std::__1::unique_ptr<disk_cache::SimpleEntryStat, std::__1::default_delete<disk_cache::SimpleEntryStat> >, std::__1::unique_ptr<disk_cache::SimpleSynchronousEntry::WriteResult, std::__1::default_delete<disk_cache::SimpleSynchronousEntry::WriteResult> >, net::IOBuffer*), std::__1::tuple<scoped_refptr<disk_cache::SimpleEntryImpl>, int, base::RepeatingCallback<void (int)>, base::internal::PassedWrapper<std::__1::unique_ptr<disk_cache::SimpleEntryStat, std::__1::default_delete<disk_cache::SimpleEntryStat> > >, base::internal::PassedWrapper<std::__1::unique_ptr<disk_cache::SimpleSynchronousEntry::WriteResult, std::__1::default_delete<disk_cache::SimpleSynchronousEntry::WriteResult> > >, base::internal::RetainedRefWrapper<net::IOBuffer> > const&, 0ul, 1ul, 2ul, 3ul, 4ul, 5ul>(void (disk_cache::SimpleEntryImpl::* const&&&)(int, base::RepeatingCallback<void (int)> const&, std::__1::unique_ptr<disk_cache::SimpleEntryStat, std::__1::default_delete<disk_cache::SimpleEntryStat> >, std::__1::unique_ptr<disk_cache::SimpleSynchronousEntry::WriteResult, std::__1::default_delete<disk_cache::SimpleSynchronousEntry::WriteResult> >, net::IOBuffer*), std::__1::tuple<scoped_refptr<disk_cache::SimpleEntryImpl>, int, base::RepeatingCallback<void (int)>, base::internal::PassedWrapper<std::__1::unique_ptr<disk_cache::SimpleEntryStat, std::__1::default_delete<disk_cache::SimpleEntryStat> > >, base::internal::PassedWrapper<std::__1::unique_ptr<disk_cache::SimpleSynchronousEntry::WriteResult, std::__1::default_delete<disk_cache::SimpleSynchronousEntry::WriteResult> > >, base::internal::RetainedRefWrapper<net::IOBuffer> > const&&&, std::__1::integer_sequence<unsigned long, 0ul, 1ul, 2ul, 3ul, 4ul, 5ul>) ./../../base/bind_internal.h:681:0
    #10 0x12cf48a1 in Run ./../../base/callback.h:96:12
    #11 0x12cf48a1 in base::debug::TaskAnnotator::RunTask(char const*, base::PendingTask*) ./../../base/debug/task_annotator.cc:101:0
    #12 0x12d922d4 in base::MessageLoop::RunTask(base::PendingTask*) ./../../base/message_loop/message_loop.cc:319:25
    #13 0x12d93e93 in DeferOrRunPendingTask ./../../base/message_loop/message_loop.cc:329:5
    #14 0x12d93e93 in base::MessageLoop::DoWork() ./../../base/message_loop/message_loop.cc:373:0
    #15 0x130941f3 in base::MessagePumpLibevent::Run(base::MessagePump::Delegate*) ./../../base/message_loop/message_pump_libevent.cc:210:31
    #16 0x12e63ebf in base::RunLoop::Run() ./../../base/run_loop.cc:102:14
    #17 0xc17d22e in content::BrowserProcessSubThread::IOThreadRun(base::RunLoop*) ./../../content/browser/browser_process_sub_thread.cc:178:11
    #18 0x12f5a75f in base::Thread::ThreadMain() ./../../base/threading/thread.cc:337:3
    #19 0x130867a7 in base::(anonymous namespace)::ThreadFunc(void*) ./../../base/threading/platform_thread_posix.cc:76:13
    #20 0x7fe5b680d183 in start_thread /build/eglibc-ripdx6/eglibc-2.19/nptl/pthread_create.c:312:0
    #21 0x7fe5ad79e03c in clone /build/eglibc-ripdx6/eglibc-2.19/misc/../sysdeps/unix/sysv/linux/x86_64/clone.S:111:0
  Uninitialized value was stored to memory at
    #0 0x15105a57 in Job ./../../net/base/prioritized_task_runner.cc:27:44
    #1 0x15105a57 in construct<net::PrioritizedTaskRunner::Job, net::PrioritizedTaskRunner::Job> ./../../buildtools/third_party/libc++/trunk/include/memory:1811:0
    #2 0x15105a57 in __construct<net::PrioritizedTaskRunner::Job, net::PrioritizedTaskRunner::Job> ./../../buildtools/third_party/libc++/trunk/include/memory:1716:0
    #3 0x15105a57 in construct<net::PrioritizedTaskRunner::Job, net::PrioritizedTaskRunner::Job> ./../../buildtools/third_party/libc++/trunk/include/memory:1562:0
    #4 0x15105a57 in void std::__1::vector<net::PrioritizedTaskRunner::Job, std::__1::allocator<net::PrioritizedTaskRunner::Job> >::__push_back_slow_path<net::PrioritizedTaskRunner::Job>(net::PrioritizedTaskRunner::Job&&) ./../../buildtools/third_party/libc++/trunk/include/vector:1580:0
    #5 0x15103647 in push_back ./../../buildtools/third_party/libc++/trunk/include/vector:1619:9
    #6 0x15103647 in net::PrioritizedTaskRunner::PostTaskAndReply(base::Location const&, base::OnceCallback<void ()>, base::OnceCallback<void ()>, unsigned int) ./../../net/base/prioritized_task_runner.cc:43:0
    #7 0x1511969a in disk_cache::SimpleEntryImpl::WriteDataInternal(int, int, net::IOBuffer*, int, base::RepeatingCallback<void (int)> const&, bool) ./../../net/disk_cache/simple/simple_entry_impl.cc:1056:29
    #8 0x15109bb3 in disk_cache::SimpleEntryImpl::RunNextOperationIfNeeded() ./../../net/disk_cache/simple/simple_entry_impl.cc:676:9
    #9 0x15123305 in disk_cache::SimpleEntryImpl::EntryOperationComplete(base::RepeatingCallback<void (int)> const&, disk_cache::SimpleEntryStat const&, int) ./../../net/disk_cache/simple/simple_entry_impl.cc:1352:3
    #10 0x15121311 in disk_cache::SimpleEntryImpl::WriteOperationComplete(int, base::RepeatingCallback<void (int)> const&, std::__1::unique_ptr<disk_cache::SimpleEntryStat, std::__1::default_delete<disk_cache::SimpleEntryStat> >, std::__1::unique_ptr<disk_cache::SimpleSynchronousEntry::WriteResult, std::__1::default_delete<disk_cache::SimpleSynchronousEntry::WriteResult> >, net::IOBuffer*) ./../../net/disk_cache/simple/simple_entry_impl.cc:1424:3
    #11 0x15128e66 in Invoke<void (disk_cache::SimpleEntryImpl::*)(int, const base::RepeatingCallback<void (int)> &, std::__1::unique_ptr<disk_cache::SimpleEntryStat, std::__1::default_delete<disk_cache::SimpleEntryStat> >, std::__1::unique_ptr<disk_cache::SimpleSynchronousEntry::WriteResult, std::__1::default_delete<disk_cache::SimpleSynchronousEntry::WriteResult> >, net::IOBuffer *), const scoped_refptr<disk_cache::SimpleEntryImpl> &, const int &, const base::RepeatingCallback<void (int)> &, std::__1::unique_ptr<disk_cache::SimpleEntryStat, std::__1::default_delete<disk_cache::SimpleEntryStat> >, std::__1::unique_ptr<disk_cache::SimpleSynchronousEntry::WriteResult, std::__1::default_delete<disk_cache::SimpleSynchronousEntry::WriteResult> >, net::IOBuffer *> ./../../base/bind_internal.h:507:12
    #12 0x15128e66 in MakeItSo<void (disk_cache::SimpleEntryImpl::*const &)(int, const base::RepeatingCallback<void (int)> &, std::__1::unique_ptr<disk_cache::SimpleEntryStat, std::__1::default_delete<disk_cache::SimpleEntryStat> >, std::__1::unique_ptr<disk_cache::SimpleSynchronousEntry::WriteResult, std::__1::default_delete<disk_cache::SimpleSynchronousEntry::WriteResult> >, net::IOBuffer *), const scoped_refptr<disk_cache::SimpleEntryImpl> &, const int &, const base::RepeatingCallback<void (int)> &, std::__1::unique_ptr<disk_cache::SimpleEntryStat, std::__1::default_delete<disk_cache::SimpleEntryStat> >, std::__1::unique_ptr<disk_cache::SimpleSynchronousEntry::WriteResult, std::__1::default_delete<disk_cache::SimpleSynchronousEntry::WriteResult> >, net::IOBuffer *> ./../../base/bind_internal.h:607:0
    #13 0x15128e66 in void base::internal::Invoker<base::internal::BindState<void (disk_cache::SimpleEntryImpl::*)(int, base::RepeatingCallback<void (int)> const&, std::__1::unique_ptr<disk_cache::SimpleEntryStat, std::__1::default_delete<disk_cache::SimpleEntryStat> >, std::__1::unique_ptr<disk_cache::SimpleSynchronousEntry::WriteResult, std::__1::default_delete<disk_cache::SimpleSynchronousEntry::WriteResult> >, net::IOBuffer*), scoped_refptr<disk_cache::SimpleEntryImpl>, int, base::RepeatingCallback<void (int)>, base::internal::PassedWrapper<std::__1::unique_ptr<disk_cache::SimpleEntryStat, std::__1::default_delete<disk_cache::SimpleEntryStat> > >, base::internal::PassedWrapper<std::__1::unique_ptr<disk_cache::SimpleSynchronousEntry::WriteResult, std::__1::default_delete<disk_cache::SimpleSynchronousEntry::WriteResult> > >, base::internal::RetainedRefWrapper<net::IOBuffer> >, void ()>::RunImpl<void (disk_cache::SimpleEntryImpl::* const&)(int, base::RepeatingCallback<void (int)> const&, std::__1::unique_ptr<disk_cache::SimpleEntryStat, std::__1::default_delete<disk_cache::SimpleEntryStat> >, std::__1::unique_ptr<disk_cache::SimpleSynchronousEntry::WriteResult, std::__1::default_delete<disk_cache::SimpleSynchronousEntry::WriteResult> >, net::IOBuffer*), std::__1::tuple<scoped_refptr<disk_cache::SimpleEntryImpl>, int, base::RepeatingCallback<void (int)>, base::internal::PassedWrapper<std::__1::unique_ptr<disk_cache::SimpleEntryStat, std::__1::default_delete<disk_cache::SimpleEntryStat> > >, base::internal::PassedWrapper<std::__1::unique_ptr<disk_cache::SimpleSynchronousEntry::WriteResult, std::__1::default_delete<disk_cache::SimpleSynchronousEntry::WriteResult> > >, base::internal::RetainedRefWrapper<net::IOBuffer> > const&, 0ul, 1ul, 2ul, 3ul, 4ul, 5ul>(void (disk_cache::SimpleEntryImpl::* const&&&)(int, base::RepeatingCallback<void (int)> const&, std::__1::unique_ptr<disk_cache::SimpleEntryStat, std::__1::default_delete<disk_cache::SimpleEntryStat> >, std::__1::unique_ptr<disk_cache::SimpleSynchronousEntry::WriteResult, std::__1::default_delete<disk_cache::SimpleSynchronousEntry::WriteResult> >, net::IOBuffer*), std::__1::tuple<scoped_refptr<disk_cache::SimpleEntryImpl>, int, base::RepeatingCallback<void (int)>, base::internal::PassedWrapper<std::__1::unique_ptr<disk_cache::SimpleEntryStat, std::__1::default_delete<disk_cache::SimpleEntryStat> > >, base::internal::PassedWrapper<std::__1::unique_ptr<disk_cache::SimpleSynchronousEntry::WriteResult, std::__1::default_delete<disk_cache::SimpleSynchronousEntry::WriteResult> > >, base::internal::RetainedRefWrapper<net::IOBuffer> > const&&&, std::__1::integer_sequence<unsigned long, 0ul, 1ul, 2ul, 3ul, 4ul, 5ul>) ./../../base/bind_internal.h:681:0
    #14 0x12cf48a1 in Run ./../../base/callback.h:96:12
    #15 0x12cf48a1 in base::debug::TaskAnnotator::RunTask(char const*, base::PendingTask*) ./../../base/debug/task_annotator.cc:101:0
    #16 0x12d922d4 in base::MessageLoop::RunTask(base::PendingTask*) ./../../base/message_loop/message_loop.cc:319:25
    #17 0x12d93e93 in DeferOrRunPendingTask ./../../base/message_loop/message_loop.cc:329:5
    #18 0x12d93e93 in base::MessageLoop::DoWork() ./../../base/message_loop/message_loop.cc:373:0
    #19 0x130941f3 in base::MessagePumpLibevent::Run(base::MessagePump::Delegate*) ./../../base/message_loop/message_pump_libevent.cc:210:31
    #20 0x12e63ebf in base::RunLoop::Run() ./../../base/run_loop.cc:102:14
    #21 0xc17d22e in content::BrowserProcessSubThread::IOThreadRun(base::RunLoop*) ./../../content/browser/browser_process_sub_thread.cc:178:11
    #22 0x12f5a75f in base::Thread::ThreadMain() ./../../base/threading/thread.cc:337:3
    #23 0x130867a7 in base::(anonymous namespace)::ThreadFunc(void*) ./../../base/threading/platform_thread_posix.cc:76:13
    #24 0x7fe5b680d183 in start_thread /build/eglibc-ripdx6/eglibc-2.19/nptl/pthread_create.c:312:0
  Uninitialized value was created by an allocation of 'job' in the stack frame of function '_ZN3net21PrioritizedTaskRunner16PostTaskAndReplyERKN4base8LocationENS1_12OnceCallbackIFvvEEES7_j'
    #0 0x15103070 in net::PrioritizedTaskRunner::PostTaskAndReply(base::Location const&, base::OnceCallback<void ()>, base::OnceCallback<void ()>, unsigned int) ./../../net/base/prioritized_task_runner.cc:38:0
SUMMARY: MemorySanitizer: use-of-uninitialized-value (/b/s/w/ir/out/Release/browser_tests+0x15106b06)
Exiting