A trunk build on Mac crashes thus:

Process:               Chromium [45659]
Path:                  /Users/USER/*/Chromium.app/Contents/MacOS/Chromium
Identifier:            org.chromium.Chromium
Version:               67.0.3393.0 (3393.0)
Code Type:             X86-64 (Native)
Parent Process:        ksh [484]
Responsible:           Terminal [321]
User ID:               501

Date/Time:             2018-04-09 11:20:31.554 -0400
OS Version:            Mac OS X 10.13.5 (17F35e)
Report Version:        12
Anonymous UUID:        0D1D2AA3-C889-FED4-E60A-C1216B8BDFAE


Time Awake Since Boot: 10000 seconds

System Integrity Protection: enabled

Crashed Thread:        0  CrBrowserMain  Dispatch queue: com.apple.main-thread

Exception Type:        EXC_BAD_ACCESS (SIGSEGV)
Exception Codes:       KERN_INVALID_ADDRESS at 0x0000000000000000

VM Regions Near 0:
--> 
    __TEXT                 000000010bc78000-000000010bc79000 [    4K] r-x/rwx SM=COW  /Users/USER/*/Chromium.app/Contents/MacOS/Chromium


Thread 0 Crashed:: CrBrowserMain  Dispatch queue: com.apple.main-thread
0   libbase.dylib                 	0x000000011341104e base::ElapsedTimer::Elapsed() const + 14 (time.h:393)
1   libchrome_dll.dylib           	0x000000010c6ddf3f metrics::DesktopProfileSessionDurationsService::OnSessionEnded(base::TimeDelta) + 143
2   libchrome_dll.dylib           	0x000000010c6df602 metrics::DesktopSessionDurationTracker::EndSession(base::TimeDelta) + 290
3   libchrome_dll.dylib           	0x000000010c6dff5f metrics::DesktopSessionDurationTracker::OnTimerFired() + 191
4   libchrome_dll.dylib           	0x000000010c6e0027 base::internal::Invoker<base::internal::BindState<void (metrics::DesktopSessionDurationTracker::*)(), base::WeakPtr<metrics::DesktopSessionDurationTracker> >, void ()>::Run(base::internal::BindStateBase*) + 183
5   libbase.dylib                 	0x00000001134122b6 base::Timer::RunScheduledTask() + 214 (callback.h:124)
6   libbase.dylib                 	0x00000001133379f3 base::debug::TaskAnnotator::RunTask(char const*, base::PendingTask*) + 323 (callback.h:95)
7   libbase.dylib                 	0x000000011337b229 base::internal::IncomingTaskQueue::RunTask(base::PendingTask*) + 121 (incoming_task_queue.cc:125)
8   libbase.dylib                 	0x000000011337fc37 base::MessageLoop::RunTask(base::PendingTask*) + 599 (vector:639)
9   libbase.dylib                 	0x000000011337fffa base::MessageLoop::DeferOrRunPendingTask(base::PendingTask) + 186 (message_loop.cc:364)
10  libbase.dylib                 	0x0000000113380555 base::MessageLoop::DoDelayedWork(base::TimeTicks*) + 677 (message_loop.cc:448)
11  libbase.dylib                 	0x0000000113384443 base::MessagePumpCFRunLoopBase::RunWork() + 67 (message_pump_mac.mm:467)
12  libbase.dylib                 	0x0000000113364d5a base::mac::CallWithEHFrame(void () block_pointer) + 10 (call_with_eh_frame_asm.S:38)
13  libbase.dylib                 	0x0000000113383d0f base::MessagePumpCFRunLoopBase::RunWorkSource(void*) + 63 (message_pump_mac.mm:441)
14  com.apple.CoreFoundation      	0x00007fff3d4fcd81 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
15  com.apple.CoreFoundation      	0x00007fff3d5b465c __CFRunLoopDoSource0 + 108
16  com.apple.CoreFoundation      	0x00007fff3d4dfd30 __CFRunLoopDoSources0 + 208
17  com.apple.CoreFoundation      	0x00007fff3d4df1ad __CFRunLoopRun + 1293
18  com.apple.CoreFoundation      	0x00007fff3d4dea07 CFRunLoopRunSpecific + 487
19  com.apple.HIToolbox           	0x00007fff3c7bcd96 RunCurrentEventLoopInMode + 286
20  com.apple.HIToolbox           	0x00007fff3c7bcb06 ReceiveNextEventCommon + 613
21  com.apple.HIToolbox           	0x00007fff3c7bc884 _BlockUntilNextEventMatchingListInModeWithFilter + 64
22  com.apple.AppKit              	0x00007fff3aa6fa73 _DPSNextEvent + 2085
23  com.apple.AppKit              	0x00007fff3b205e34 -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] + 3044
24  libchrome_dll.dylib           	0x000000010c3a1400 __71-[BrowserCrApplication nextEventMatchingMask:untilDate:inMode:dequeue:]_block_invoke + 64
25  libbase.dylib                 	0x0000000113364d5a base::mac::CallWithEHFrame(void () block_pointer) + 10 (call_with_eh_frame_asm.S:38)
26  libchrome_dll.dylib           	0x000000010c3a1344 -[BrowserCrApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 164
27  com.apple.AppKit              	0x00007fff3aa64885 -[NSApplication run] + 764
28  libbase.dylib                 	0x00000001133854ec base::MessagePumpNSApplication::DoRun(base::MessagePump::Delegate*) + 364 (message_pump_mac.mm:831)
29  libbase.dylib                 	0x000000011338375e base::MessagePumpCFRunLoopBase::Run(base::MessagePump::Delegate*) + 110 (message_pump_mac.mm:311)
30  libbase.dylib                 	0x000000011337f559 base::MessageLoop::Run(bool) + 169 (message_loop.cc:308)
31  libbase.dylib                 	0x00000001133c1089 base::RunLoop::Run() + 249 (run_loop.cc:133)
32  libchrome_dll.dylib           	0x000000010c3a80c8 ChromeBrowserMainParts::MainMessageLoopRun(int*) + 312
33  libcontent.dylib              	0x0000000115ad2cd4 content::BrowserMainLoop::RunMainMessageLoopParts() + 52 (browser_main_loop.cc:1061)
34  libcontent.dylib              	0x0000000115ad5e06 content::BrowserMainRunnerImpl::Run() + 102 (memory:2603)
35  libcontent.dylib              	0x0000000115acf2b9 content::BrowserMain(content::MainFunctionParams const&) + 233 (browser_main.cc:46)
36  libcontent.dylib              	0x000000011663175a content::ContentMainRunnerImpl::Run() + 554 (content_main_runner.cc:706)
37  libembedder.dylib             	0x000000011327f806 service_manager::Main(service_manager::MainParams const&) + 2470 (main.cc:453)
38  libcontent.dylib              	0x0000000116630b54 content::ContentMain(content::ContentMainParams const&) + 68 (content_main.cc:19)
39  libchrome_dll.dylib           	0x000000010bd175a3 ChromeMain + 179
40  org.chromium.Chromium         	0x000000010bc78de4 main + 404 (chrome_exe_main_mac.cc:169)
41  libdyld.dylib                 	0x00007fff65db1015 start + 1