UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.113 Safari/537.36

Steps to reproduce the problem:
1. install depot_tools
2. get the code
3. gn gen out/Release
4. use "use_udev = false" in args.gn
5. #error "USE_UDEV not defined"

What is the expected behavior?
Compiling a version of chrome which does not rely on udev.

What went wrong?
~/chromium/src$ ninja -C out/ARM_release chrome
ninja: Entering directory `out/ARM_release'
[1/1] Regenerating ninja files
[48/15232] CXX obj/device/serial/serial/serial_device_enumerator_linux.o
FAILED: obj/device/serial/serial/serial_device_enumerator_linux.o 
../../third_party/llvm-build/Release+Asserts/bin/clang++ -MMD -MF obj/device/serial/serial/serial_device_enumerator_linux.o.d -DV8_DEPRECATION_WARNINGS -DUSE_AURA=1 -DUSE_NSS_CERTS=1 -DUSE_OZONE=1 -DDISABLE_NACL -DFULL_SAFE_BROWSING -DSAFE_BROWSING_CSD -DSAFE_BROWSING_DB_LOCAL -DCHROMIUM_BUILD -DFIELDTRIAL_TESTING_ENABLED -DCR_CLANG_REVISION=\"310694-2\" -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS -D_LIBCXXABI_DISABLE_VISIBILITY_ANNOTATIONS -DNDEBUG -DNVALGRIND -DDYNAMIC_ANNOTATIONS_ENABLED=0 -DGOOGLE_PROTOBUF_NO_RTTI -DGOOGLE_PROTOBUF_NO_STATIC_INITIALIZER -DHAVE_PTHREAD -I../.. -Igen -I../../third_party/protobuf/src -Igen/protoc_out -I../../third_party/protobuf/src -I../../third_party/boringssl/src/include -I../../build/linux/debian_jessie_arm-sysroot/usr/include/nss -I../../build/linux/debian_jessie_arm-sysroot/usr/include/nspr -I../../third_party/re2/src -fno-strict-aliasing --param=ssp-buffer-size=4 -fstack-protector -Wno-builtin-macro-redefined -D__DATE__= -D__TIME__= -D__TIMESTAMP__= -funwind-tables -fPIC -pipe -pthread -fcolor-diagnostics --target=arm-linux-gnueabihf -march=armv7-a -mfloat-abi=hard -mtune=generic-armv7-a -mfpu=neon -mthumb -Wall -Werror -Wextra -Wno-missing-field-initializers -Wno-unused-parameter -Wno-c++11-narrowing -Wno-covered-switch-default -Wno-unneeded-internal-declaration -Wno-inconsistent-missing-override -Wno-undefined-var-template -Wno-nonportable-include-path -Wno-address-of-packed-member -Wno-unused-lambda-capture -Wno-user-defined-warnings -Wno-enum-compare-switch -O2 -fno-ident -fdata-sections -ffunction-sections -fomit-frame-pointer -g0 -fvisibility=hidden -Xclang -load -Xclang ../../third_party/llvm-build/Release+Asserts/lib/libFindBadConstructs.so -Xclang -add-plugin -Xclang find-bad-constructs -Xclang -plugin-arg-find-bad-constructs -Xclang check-auto-raw-pointer -Xclang -plugin-arg-find-bad-constructs -Xclang check-ipc -Wheader-hygiene -Wstring-conversion -Wtautological-overlap-compare -Wno-header-guard -std=gnu++14 -fno-rtti -nostdinc++ -isystem../../buildtools/third_party/libc++/trunk/include -isystem../../buildtools/third_party/libc++abi/trunk/include -isystem../../buildtools/third_party/libunwind/trunk/include --sysroot=../../build/linux/debian_jessie_arm-sysroot -fno-exceptions -fvisibility-inlines-hidden -c ../../device/serial/serial_device_enumerator_linux.cc -o obj/device/serial/serial/serial_device_enumerator_linux.o
In file included from ../../device/serial/serial_device_enumerator_linux.cc:5:
In file included from ../../device/serial/serial_device_enumerator_linux.h:10:
In file included from ../../device/udev_linux/scoped_udev.h:10:
../../device/udev_linux/udev.h:15:2: error: "USE_UDEV not defined"
#error "USE_UDEV not defined"
 ^
In file included from ../../device/serial/serial_device_enumerator_linux.cc:5:
In file included from ../../device/serial/serial_device_enumerator_linux.h:10:
../../device/udev_linux/scoped_udev.h:13:2: error: "USE_UDEV not defined"
#error "USE_UDEV not defined"

Did this work before? N/A 

Chrome version: 60.0.3200  Channel: stable
OS Version: Ubuntu Trusty
Flash Version: 

I'm trying to build chrome so I can use it in headless mode for an arm device which does not have udev support.