Sample failing builder (there are many):
https://uberchromegw.corp.google.com/i/chromiumos.chromium/builders/x86-generic-tot-chromium-pfq-informational/builds/9582

Relevant log snippet:
FAILED: obj/chrome/browser/chromeos/chromeos/device_cloud_policy_initializer.o 
chromeos-chrome-55.0.2854.0_alpha-r1: i686-pc-linux-gnu-g++ -B/usr/x86_64-pc-linux-gnu/i686-pc-linux-gnu/binutils-bin/2.25.51-gold -MMD -MF obj/chrome/browser/chromeos/chromeos/device_cloud_policy_initializer.o.d -DUSE_CRAS -DV8_DEPRECATION_WARNINGS -DENABLE_MDNS=1 -DENABLE_NOTIFICATIONS -DENABLE_PEPPER_CDMS -DENABLE_PLUGINS=1 -DENABLE_PDF=1 -DENABLE_PRINTING=1 -DENABLE_BASIC_PRINTING=1 -DENABLE_PRINT_PREVIEW=1 -DENABLE_SPELLCHECK=1 -DUSE_UDEV -DUI_COMPOSITOR_IMAGE_TRANSPORT -DUSE_ASH=1 -DUSE_AURA=1 -DUSE_DEFAULT_RENDER_THEME=1 -DUSE_NSS_CERTS=1 -DUSE_OZONE=1 -DENABLE_WEBRTC=1 -DENABLE_EXTENSIONS=1 -DENABLE_TASK_MANAGER=1 -DENABLE_THEMES=1 -DENABLE_CAPTIVE_PORTAL_DETECTION=1 -DENABLE_SESSION_SERVICE=1 -DENABLE_APP_LIST=1 -DENABLE_SUPERVISED_USERS=1 -DENABLE_SERVICE_DISCOVERY=1 -DIMAGE_LOADER_EXTENSION=1 -DENABLE_WAYLAND_SERVER=1 -DFULL_SAFE_BROWSING -DSAFE_BROWSING_CSD -DSAFE_BROWSING_DB_LOCAL -DCHROMIUM_BUILD -DENABLE_MEDIA_ROUTER=1 -DFIELDTRIAL_TESTING_ENABLED -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D_FORTIFY_SOURCE=2 -DOS_CHROMEOS -DNDEBUG -DNVALGRIND -DDYNAMIC_ANNOTATIONS_ENABLED=0 -DUSE_EGL -DTOOLKIT_VIEWS=1 -DSK_IGNORE_DW_GRAY_FIX -DSK_IGNORE_LINEONLY_AA_CONVEX_PATH_OPTS -DSK_SUPPORT_GPU=1 -DGOOGLE_PROTOBUF_NO_RTTI -DGOOGLE_PROTOBUF_NO_STATIC_INITIALIZER -DHAVE_PTHREAD -DU_USING_ICU_NAMESPACE=0 -DU_ENABLE_DYLOAD=0 -DU_NOEXCEPT= -DU_STATIC_IMPLEMENTATION -DICU_UTIL_DATA_IMPL=ICU_UTIL_DATA_FILE -DV8_USE_EXTERNAL_STARTUP_DATA -DENABLE_WEBSOCKETS -DMESA_EGL_NO_X11_HEADERS -DLEVELDB_PLATFORM_CHROMIUM=1 -DFEATURE_ENABLE_SSL -DFEATURE_ENABLE_VOICEMAIL -DEXPAT_RELATIVE_PATH -DGTEST_RELATIVE_PATH -DNO_MAIN_THREAD_WRAPPING -DNO_SOUND_SYSTEM -DWEBRTC_CHROMIUM_BUILD -DWEBRTC_POSIX -DWEBRTC_LINUX -DCHROMEOS -DSSL_USE_OPENSSL -DHAVE_OPENSSL_SSL_H -DFEATURE_ENABLE_SSL -DLOGGING=1 -DNO_MAIN_THREAD_WRAPPING -I../../../../../../../home/chrome-bot/chrome_root/src -Igen -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/khronos -I../../../../../../../home/chrome-bot/chrome_root/src/gpu -Igen/ash/common/strings -Igen/ash/resources -Igen/chrome -Igen/chrome -Igen/chrome -Igen/chrome -I../../../../../../../home/chrome-bot/chrome_root/src/skia/config -I../../../../../../../home/chrome-bot/chrome_root/src/skia/ext -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/skia/include/c -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/skia/include/config -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/skia/include/core -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/skia/include/effects -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/skia/include/images -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/skia/include/lazy -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/skia/include/pathops -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/skia/include/pdf -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/skia/include/pipe -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/skia/include/ports -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/skia/include/utils -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/skia/include/gpu -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/skia/src/gpu -Igen/ui/chromeos/resources -Igen/ui/chromeos/strings -Igen/ui/resources -Igen/ui/resources -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/protobuf/src -Igen/protoc_out -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/protobuf/src -Igen -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/ced/src -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/icu/source/common -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/icu/source/i18n -Igen/components/strings -Igen/components/strings -Igen/components/strings -Igen/components/strings -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/WebKit -Igen/third_party/WebKit -I../../../../../../../home/chrome-bot/chrome_root/src/v8/include -Igen -I../../../../../../../home/chrome-bot/chrome_root/src/v8/include -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/libwebm/source -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/opus/src/include -I/build/x86-generic/usr/include/nss -I/build/x86-generic/usr/include/nspr -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/boringssl/src/include -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/re2/src -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/mesa/src/include -Igen/extensions -Igen/extensions -Igen/extensions -Igen -Igen/extensions/strings -I/build/x86-generic/usr/include/dbus-1.0 -I/build/x86-generic/usr/lib/dbus-1.0/include -Igen -Igen/components -Igen/components -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/cacheinvalidation/overrides -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/cacheinvalidation/src -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/leveldatabase -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/leveldatabase/src -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/leveldatabase/src/include -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/webrtc_overrides -I../../../../../../../home/chrome-bot/chrome_root/src/testing/gtest/include -I../../../../../../../home/chrome-bot/chrome_root/src/third_party -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/webrtc_overrides -I../../../../../../../home/chrome-bot/chrome_root/src/third_party -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/jsoncpp/overrides/include -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/jsoncpp/source/include -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/libusb/src/libusb -I../../../../../../../home/chrome-bot/chrome_root/src/third_party/zlib -Igen/ui/views/resources -Igen/ui/file_manager -fno-strict-aliasing -funwind-tables -fPIC -pipe -pthread -m32 -msse2 -mfpmath=sse -mmmx -Wall -Werror -Wno-unused-local-typedefs -Wno-maybe-uninitialized -Wno-missing-field-initializers -Wno-unused-parameter -O2 -fno-ident -fdata-sections -ffunction-sections -g2 -gsplit-dwarf --sysroot=../../../../../../../build/x86-generic -fvisibility=hidden -fno-threadsafe-statics -fvisibility-inlines-hidden -std=gnu++11 -Wno-narrowing -Wno-literal-suffix -fno-rtti -fno-exceptions -march=i686 -pipe -march=i686 -pipe -pipe -march=i686 -mfpmath=sse -mmmx -msse -msse2 -msse3 -D__google_stl_debug_vector=1  -c ../../../../../../../home/chrome-bot/chrome_root/src/chrome/browser/chromeos/policy/device_cloud_policy_initializer.cc -o obj/chrome/browser/chromeos/chromeos/device_cloud_policy_initializer.o
chromeos-chrome-55.0.2854.0_alpha-r1: ../../../../../../../home/chrome-bot/chrome_root/src/chrome/browser/chromeos/policy/device_cloud_policy_initializer.cc:18:76: fatal error: chrome/browser/chromeos/attestation/attestation_signed_data.pb.h: No such file or directory
chromeos-chrome-55.0.2854.0_alpha-r1:  #include "chrome/browser/chromeos/attestation/attestation_signed_data.pb.h"
chromeos-chrome-55.0.2854.0_alpha-r1:                                                                             ^
chromeos-chrome-55.0.2854.0_alpha-r1: compilation terminated.



CL responsible:
https://codereview.chromium.org/2297193006