https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/mac-rel and https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/mac-dbg look flaky.

[2374/61420] ACTION //content/test:content_nocompile_tests_run_nocompile(//build/toolchain/mac:clang_x64)
FAILED: gen/content/test/browser_task_traits_unittest_nc.cc 
python ../../tools/nocompile_driver.py 4 ../../content/public/browser/browser_task_traits_unittest.nc gen/content/test/browser_task_traits_unittest_nc.cc -- -nostdinc++ -isystem../../buildtools/third_party/libc++/trunk/include -isystem../../buildtools/third_party/libc++abi/trunk/include -std=c++14 -Wall -Werror -Wfatal-errors -Wthread-safety -I../../ -Igen --sysroot ../../build/mac_files/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.12.sdk
In file included from ../../content/public/browser/browser_task_traits_unittest.nc:9:
In file included from ../../content/public/browser/browser_task_traits.h:11:
In file included from ../../content/public/browser/browser_thread.h:13:
../../base/location.h:14:10: fatal error: 'base/debug/debugging_buildflags.h' file not found
#include "base/debug/debugging_buildflags.h"
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.