Example failing builds:

https://ci.chromium.org/buildbot/tryserver.chromium.linux/linux_chromium_chromeos_rel_ng/526133
https://ci.chromium.org/buildbot/tryserver.chromium.linux/linux_chromium_chromeos_rel_ng/526484

Log excerpt:

https://luci-logdog.appspot.com/v/?s=chromium%2Fbb%2Ftryserver.chromium.linux%2Flinux_chromium_chromeos_rel_ng%2F526133%2F%2B%2Frecipes%2Fsteps%2Fbrowser_tests__with_patch_%2F0%2Flogs%2FChromeTracingDelegateBrowserTestOnStartup.StartupTracingThrottle%2F0

[ RUN      ] ChromeTracingDelegateBrowserTestOnStartup.StartupTracingThrottle
[5115:5115:1010/213414.493616:WARNING:chrome_browser_main_chromeos.cc(620)] Running as stub user with profile dir: test-user
[5148:5148:1010/213414.567863:ERROR:gpu_info.cc(103)] No active GPU found, returning primary GPU.
[5115:5115:1010/213414.624387:ERROR:input_method_manager_impl.cc(1031)] IMEEngine for "fgoepimhcoialccpbmpnnblemnepkkao" is not registered
[5115:5129:1010/213414.633019:WARNING:freezer_cgroup_process_manager.cc(62)] Cgroup freezer does not exist or is not writable. Unable to freeze renderer processes.
[5115:5140:1010/213414.646546:WARNING:child_process_launcher_helper_posix.cc(118)] Ignoring invalid file v8_context_snapshot.bin
[5115:5115:1010/213414.758199:ERROR:touch_devices_controller.cc(22)] Failed to set touchpad enabled state.
[5148:5148:1010/213414.772324:WARNING:internal_linux.cc(64)] Failed to read /proc/self/stat
[5115:5115:1010/213414.795035:INFO:chrome_cryptauth_service.cc(230)] Refresh token not yet available; waiting before starting CryptAuth managers.
BrowserTestBase received signal: Segmentation fault. Backtrace:
../../third_party/tcmalloc/chromium/src/free_list.h:118] Memory corruption detected.
BrowserTestBase received signal: Segmentation fault. Backtrace:
#0 0x000003a3d54c base::debug::StackTrace::StackTrace()
#1 0x0000040617c8 content::(anonymous namespace)::DumpStackTraceSignalHandler()
#2 0x7fd5d3fe4cb0 <unknown>
#3 0x000001a048c0 <unknown>
#4 0x000001a08667 tcmalloc::Log()
#5 0x000001a07fa4 tcmalloc::FL_PopRange()
#6 0x000001a0c33a tcmalloc::ThreadCache::ReleaseToCentralCache()
#7 0x000001a0c51d tcmalloc::ThreadCache::ListTooLong()
#8 0x000001a0f14e (anonymous namespace)::do_free_with_callback()
#9 0x000002174dea mojo::edk::ports::UserMessageEvent::~UserMessageEvent()
#10 0x00000217779b

This seems serious even though the flakiness level on the commit queue is fairly low. Could someone please take this? Thanks.