There are multiple failing tests on multiple mac trybots in chromium.gpu.fyi.

Mac FYI Experimental Release (Intel)
https://ci.chromium.org/buildbot/chromium.gpu.fyi/Mac%20FYI%20Experimental%20Release%20%28Intel%29/523

Mac FYI Experimental Retina Release (NVIDIA)
https://ci.chromium.org/buildbot/chromium.gpu.fyi/Mac%20FYI%20Experimental%20Retina%20Release%20%28NVIDIA%29/130

Mac FYI GPU ASAN Release
https://ci.chromium.org/buildbot/chromium.gpu.fyi/Mac%20FYI%20GPU%20ASAN%20Release/195

Multiple failing test suites on each bot. The browser process is crashing on startup in all cases with a similar stack trace:

[0305/210338.148154:FATAL:string_piece.h(223)] Check failed: i < length_. 
0   crashpad_handler                    0x000000010f68df1c base::debug::StackTrace::StackTrace(unsigned long) + 28
1   crashpad_handler                    0x000000010f6ac980 logging::LogMessage::~LogMessage() + 224
2   crashpad_handler                    0x000000010f77c897 bool (anonymous namespace)::StringToIntegerInternal<(anonymous namespace)::StringToIntTraits>(base::BasicStringPiece<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > const&, (anonymous namespace)::StringToIntTraits::IntType*) + 151
3   crashpad_handler                    0x000000010f66e64e crashpad::HandlerMain(int, char**, std::__1::vector<std::__1::unique_ptr<crashpad::UserStreamDataSource, std::__1::default_delete<crashpad::UserStreamDataSource> >, std::__1::allocator<std::__1::unique_ptr<crashpad::UserStreamDataSource, std::__1::default_delete<crashpad::UserStreamDataSource> > > > const*) + 1726
4   libdyld.dylib                       0x00007fff7eb26015 start + 1
[0305/210338.162271:ERROR:file_io.cc(89)] ReadExactly: expected 8, observed 0
[427:775:0305/210338.840779:FATAL:crashpad_client_mac.cc(491)] Check failed: exception_port_.is_valid(). 
0   Chromium Framework                  0x0000000116d6a4dc base::debug::StackTrace::StackTrace(unsigned long) + 28
1   Chromium Framework                  0x0000000116d8f3f0 logging::LogMessage::~LogMessage() + 224
2   Chromium Framework                  0x0000000117bfb34d crashpad::CrashpadClient::GetHandlerMachPort() const + 93
3   Chromium Framework                  0x00000001169768b0 -[AlertDispatcherImpl serviceProxy] + 80
4   Chromium Framework                  0x000000011697609b -[AlertDispatcherImpl getDisplayedAlertsForProfileId:incognito:notificationCenter:callback:] + 107
5   Chromium Framework                  0x0000000116974fa3 NotificationPlatformBridgeMac::GetDisplayed(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, bool, base::RepeatingCallback<void (std::__1::unique_ptr<std::__1::set<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::less<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > >, std::__1::default_delete<std::__1::set<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::less<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > > > >, bool)> const&) const + 83
6   Chromium Framework                  0x0000000116971b9a NotificationDisplayServiceImpl::GetDisplayed(base::RepeatingCallback<void (std::__1::unique_ptr<std::__1::set<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::less<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > >, std::__1::default_delete<std::__1::set<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::less<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > > > >, bool)> const&) + 122
7   Chromium Framework                  0x000000011697adfe PlatformNotificationServiceImpl::GetDisplayedNotifications(content::BrowserContext*, base::RepeatingCallback<void (std::__1::unique_ptr<std::__1::set<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::less<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > >, std::__1::default_delete<std::__1::set<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::less<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > > > >, bool)> const&) + 382
8   Chromium Framework                  0x0000000114d50128 content::PlatformNotificationContextImpl::Initialize() + 376
9   Chromium Framework                  0x0000000114f750ce content::StoragePartitionImpl::Create(content::BrowserContext*, bool, base::FilePath const&) + 2654
10  Chromium Framework                  0x0000000114f7c740 content::StoragePartitionImplMap::Get(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, bool, bool) + 272
11  Chromium Framework                  0x0000000114a2538d content::(anonymous namespace)::GetStoragePartitionFromConfig(content::BrowserContext*, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, bool, bool) + 157
12  Chromium Framework                  0x0000000114a254c9 content::BrowserContext::GetDefaultStoragePartition(content::BrowserContext*) + 57
13  Chromium Framework                  0x0000000116a3b40e ProfileImpl::DoFinalInit() + 2462
14  Chromium Framework                  0x0000000116a3d312 ProfileImpl::OnLocaleReady() + 1218
15  Chromium Framework                  0x0000000116a3a9cd ProfileImpl::OnPrefsLoaded(Profile::CreateMode, bool) + 173
16  Chromium Framework                  0x0000000116a3a5d9 ProfileImpl::ProfileImpl(base::FilePath const&, Profile::Delegate*, Profile::CreateMode, scoped_refptr<base::SequencedTaskRunner>) + 2425
17  Chromium Framework                  0x0000000116a38849 Profile::CreateProfile(base::FilePath const&, Profile::Delegate*, Profile::CreateMode) + 345
18  Chromium Framework                  0x0000000116a58947 ProfileManager::CreateProfileHelper(base::FilePath const&) + 71
19  Chromium Framework                  0x0000000116a51d4a ProfileManager::CreateAndInitializeProfile(base::FilePath const&) + 138
20  Chromium Framework                  0x0000000116a51a0e ProfileManager::GetProfile(base::FilePath const&) + 78
21  Chromium Framework                  0x000000011a162465 GetStartupProfile(base::FilePath const&, base::CommandLine const&) + 69
22  Chromium Framework                  0x000000011685bd71 ChromeBrowserMainParts::PreMainMessageLoopRunImpl() + 2097
23  Chromium Framework                  0x000000011685b43e ChromeBrowserMainParts::PreMainMessageLoopRun() + 62
24  Chromium Framework                  0x0000000114a2c3d3 content::BrowserMainLoop::PreMainMessageLoopRun() + 67
25  Chromium Framework                  0x0000000114f73145 content::StartupTaskRunner::RunAllTasksNow() + 117
26  Chromium Framework                  0x0000000114a2abbd content::BrowserMainLoop::CreateStartupTasks() + 765
27  Chromium Framework                  0x0000000114a2f2c3 content::BrowserMainRunnerImpl::Initialize(content::MainFunctionParams const&) + 99
28  Chromium Framework                  0x0000000114a28912 content::BrowserMain(content::MainFunctionParams const&) + 210
29  Chromium Framework                  0x00000001167ed2cb content::ContentMainRunnerImpl::Run() + 555
30  Chromium Framework                  0x0000000118962747 service_manager::Main(service_manager::MainParams const&) + 2471
31  Chromium Framework                  0x00000001167ec664 content::ContentMain(content::ContentMainParams const&) + 68
32  Chromium Framework                  0x000000011390cd13 ChromeMain + 179
33  Chromium                            0x000000010b0f9de4 main + 404
34  libdyld.dylib                       0x00007fff7eb26015 start + 1

The smallest revision range for first failure is 541009-541021.

https://chromium.googlesource.com/chromium/src/+log/9dd1ef42a8a33c5ba09ec645150f580724979b36%5E..fc897c242fac290704e0f3e9297ce97012e849f0?pretty=fuller&n=

Looking now to see if anything stands out.