args.list

aec_debug_dump  Default = false
    //third_party/webrtc/modules/audio_processing/BUILD.gn:15
    Outputs some low-level debug files.

aec_untrusted_delay_for_testing  Default = false
    //third_party/webrtc/modules/audio_processing/BUILD.gn:20
    Disables the usual mode where we trust the reported system delay
    values the AEC receives. The corresponding define is set appropriately
    in the code, but it can be force-enabled here for testing.

android_full_debug  Default = false
    //build/config/compiler/BUILD.gn:29
    Normally, Android builds are lightly optimized, even for debug builds, to
    keep binary size down. Setting this flag to true disables such optimization

android_java_ui  Default = false
    //chrome/common/features.gni:15
    Whether the Java UI is being used (Java infobars and popups, Java native
    settings and first run experience, sign-in etc.).
    Default to true if compiling for android, but allow this being overriden
    through the environment.

binutils_path  Default = "../../third_party/binutils/Linux_x64/Release/bin"
    //build/config/compiler/BUILD.gn:36

blink_asserts_off_in_release  Default = false
    //third_party/WebKit/Source/config.gni:25
    If true, force blink asserts to be off in a release build.  When false,
    blink asserts in release build may be controlled by DCHECK_ALWAYS_ON.

blink_gc_plugin  Default = true
    //third_party/WebKit/Source/config.gni:21
    Set to true to enable the clang plugin that checks the usage of the Blink
    garbage-collection infrastructure during compilation.

build_with_libjingle  Default = true
    //third_party/webrtc/build/webrtc.gni:14

build_with_mozilla  Default = false
    //third_party/webrtc/build/webrtc.gni:51
    Enable to use the Mozilla internal settings.

chrome_pgo_phase  Default = 0
    //chrome/BUILD.gn:29
    Specify the current PGO phase, only used for the Windows MSVS build. Here's
    the different values that can be used:
        0 : Means that PGO is turned off.
        1 : Used during the PGI (instrumentation) phase.
        2 : Used during the PGO (optimization) phase.
   
    TODO(sebmarchand): Add support for the PGU (update) phase.

cld2_table_size  Default = 2
    //third_party/cld_2/BUILD.gn:11

content_shell_product_name  Default = "Content Shell"
    //content/shell/BUILD.gn:16

content_shell_version  Default = "99.77.34.5"
    //content/shell/BUILD.gn:17

current_cpu  Default = ""
    (Internally set)

current_os  Default = ""
    (Internally set)

custom_toolchain  Default = ""
    //build/config/BUILDCONFIG.gn:130
    Allows the path to a custom target toolchain to be injected as a single
    argument, and set as the default toolchain.

dcheck_always_on  Default = false
    //build/config/BUILD.gn:38
    Set to true to enable dcheck in Release builds.

debug_devtools  Default = false
    //build/config/features.gni:51
    If debug_devtools is set to true, JavaScript files for DevTools are stored
    as is and loaded from disk. Otherwise, a concatenated file is stored in
    resources.pak. It is still possible to load JS files from disk by passing
    --debug-devtools cmdline switch.

disable_display  Default = false
    //build/config/chromecast_build.gni:14
    Set this true for an audio-only Chromecast build.

disable_file_support  Default = false
    //net/BUILD.gn:46
    Disables support for file URLs.  File URL support requires use of icu.

disable_ftp_support  Default = false
    //net/BUILD.gn:54

dont_embed_build_metadata  Default = true
    //build/config/BUILD.gn:35
    Set to true to not store any build metadata, e.g. ifdef out all __DATE__
    and __TIME__. Set to 0 to reenable the use of these macros in the code
    base. See http://crbug.com/314403.
   
    Continue to embed build meta data in Official builds, basically the
    time it was built.
    TODO(maruel): This decision should be revisited because having an
    official deterministic build has high value too but MSVC toolset can't
    generate anything deterministic with WPO enabled AFAIK.

enable_ac3_eac3_audio_demuxing  Default = false
    //media/media_options.gni:55
    Enables AC3/EAC3 audio demuxing. This is enabled only on Chromecast, since
    it only provides demuxing, and is only useful for AC3/EAC3 audio
    pass-through to HDMI sink on Chromecast.

enable_app_list  Default = true
    //build/config/features.gni:79

enable_autofill_dialog  Default = true
    //build/config/features.gni:83

enable_background  Default = true
    //build/config/features.gni:69
    Enables support for background apps.

enable_bidirectional_stream  Default = false
    //net/BUILD.gn:49
    Enables BidirectionalStream; Used in cronet, disabled by default.

enable_browser_cdms  Default = false
    //build/config/features.gni:94
    Enables browser side Content Decryption Modules. Required for embedders
    (e.g. Android and ChromeCast) that use a browser side CDM.

enable_captive_portal_detection  Default = true
    //build/config/features.gni:71

enable_configuration_policy  Default = true
    //build/config/features.gni:66

enable_debugallocation  Default = true
    //base/allocator/BUILD.gn:16
    Provide a way to force disable debugallocation in Debug builds,
    e.g. for profiling (it's more rare to profile Debug builds,
    but people sometimes need to do that).

enable_extensions  Default = true
    //build/config/features.gni:28

enable_full_stack_frames_for_profiling  Default = false
    //build/config/compiler/BUILD.gn:44
    Compile in such a way as to make it possible for the profiler to unwind full
    stack frames. Setting this flag has a large effect on the performance of the
    generated code than just setting profiling, but gives the profiler more
    information to analyze.
    Requires profiling to be set to true.

enable_google_now  Default = true
    //chrome/common/features.gni:9

enable_hangout_services_extension  Default = false
    //build/config/features.gni:98
    Hangout services is an extension that adds extra features to Hangouts.
    For official GYP builds, this flag is set.

enable_hevc_demuxing  Default = false
    //media/media_options.gni:61
    Enable HEVC/H265 demuxing. Actual decoding must be provided by the
    platform. Enable by default for Chromecast.

enable_hotwording  Default = false
    //chrome/browser/BUILD.gn:28
    'Ok Google' hotwording is disabled by default. Set to true to enable. (This
    will download a closed-source NaCl module at startup.) Chrome-branded
    ChromeOS builds have this enabled by default.

enable_internal_app_remoting_targets  Default = false
    //remoting/remoting_options.gni:13
    Set this to enable building internal AppRemoting apps.

enable_iterator_debugging  Default = true
    //build/config/BUILD.gn:24
    When set (the default) enables C++ iterator debugging in debug builds.
    Iterator debugging is always off in release builds (technically, this flag
    affects the "debug" config, which is always available but applied by
    default only in debug builds).
   
    Iterator debugging is generally useful for catching bugs. But it can
    introduce extra locking to check the state of an iterator against the state
    of the current object. For iterator- and thread-heavy code, this can
    significantly slow execution.

enable_kasko  Default = false
    //third_party/kasko/BUILD.gn:10
    Enable the Kasko crash reporter. Enabled by default on syzyasan build.

enable_kasko_hang_reports  Default = false
    //third_party/kasko/BUILD.gn:13
    Enable the reporting of browser hangs with Kasko.

enable_mdns  Default = true
    //build/config/features.gni:26
    Multicast DNS.

enable_media_router  Default = true
    //build/config/features.gni:58
    Enables the Media Router.

enable_mojo_media  Default = "none"
    //media/media_options.gni:69
    Experiment to enable mojo media application: http://crbug.com/431776
    Valid options are:
    - "none": Do not use mojo media application.
    - "browser": Use mojo media application hosted in the browser process.
    - "gpu": Use mojo media application hosted in the gpu process.
    - "utility": Use mojo media application hosted in the utility process.

enable_mse_mpeg2ts_stream_parser  Default = false
    //media/media_options.gni:57

enable_nacl  Default = true
    //build/config/features.gni:37
    Enables Native Client support.
    TODO(GYP): Get NaCl linking on other platforms.
    Also, see if we can always get rid of enable_nacl_untrusted and
    enable_pnacl and always build them if enable_nacl is true.
    Eventually we want this to be just the first line.

enable_nacl_untrusted  Default = ""
    //build/config/features.gni:44
    These default to the non-Boolean "" so that code below can default
    them to the explicitly-set value of enable_nacl, whereas initializing
    them here uses the default value of enable_nacl above and ignores any
    args.gn setting.

enable_nocompile_tests  Default = false
    //build/nocompile.gni:62
    TODO(crbug.com/105388): Disabled until http://crbug.com/105388 is resolved.

enable_oilpan  Default = false
    //third_party/WebKit/public/features.gni:7
    Enables the Oilpan garbage-collection infrastructure.

enable_one_click_signin  Default = true
    //build/config/features.gni:85

enable_pdf  Default = true
    //build/config/features.gni:30

enable_plugin_installation  Default = true
    //build/config/features.gni:77

enable_plugins  Default = true
    //build/config/features.gni:29

enable_pnacl  Default = ""
    //build/config/features.gni:45

enable_profiling  Default = false
    //build/config/compiler/compiler.gni:20
    Compile in such a way as to enable profiling of the generated code. For
    example, don't omit the frame pointer and leave in symbols.

enable_remoting  Default = true
    //build/config/features.gni:87

enable_remoting_jscompile  Default = false
    //remoting/remoting_options.gni:10
    Set this to run the jscompile checks after building the webapp.

enable_resource_whitelist_generation  Default = false
    //tools/grit/grit_rule.gni:88
    Enables used resource whitelist generation.

enable_session_service  Default = true
    //build/config/features.gni:75
    Enables use of the session service, which is enabled by default.
    Android stores them separately on the Java side.

enable_supervised_users  Default = true
    //build/config/features.gni:81

enable_topchrome_md  Default = true
    //build/config/ui.gni:52
    Indicates if material design elements in the top chrome of the browser are
    enabled.

enable_video_hole  Default = false
    //build/config/features.gni:90
    Enable hole punching for the protected video.

enable_wayland_server  Default = false
    //build/config/ui.gni:55
    Indicates if Wayland display server support is enabled.

enable_webrtc  Default = true
    //build/config/features.gni:55
    Enables WebRTC.
    TODO(GYP) make mac work.

enable_websockets  Default = true
    //net/BUILD.gn:53
    WebSockets and socket stream code are not used on iOS and are optional in
    cronet.

enable_widevine  Default = false
    //third_party/widevine/cdm/widevine.gni:7
    Allow widevinecdmadapter to be built in Chromium.

enable_wifi_display  Default = false
    //build/config/features.gni:120
    Enables Wi-Fi Display functionality

ffmpeg_branding  Default = "Chromium"
    //third_party/ffmpeg/ffmpeg_options.gni:29
    Controls whether we build the Chromium or Google Chrome version of FFmpeg.
    The Google Chrome version contains additional codecs. Typical values are
    Chromium, Chrome, ChromiumOS, and ChromeOS.

fieldtrial_testing_like_official_build  Default = false
    //build/config/features.gni:115
    Set to true make a build that disables activation of field trial tests
    specified in testing/variations/fieldtrial_testing_config_*.json.
    Note: this setting is ignored if is_chrome_branded.

gold_path  Default = false
    //build/config/compiler/BUILD.gn:53
    When we are going to use gold we need to find it.
    This is initialized below, after use_gold might have been overridden.

goma_dir  Default = "C:\goma\goma-win"
    //build/toolchain/goma.gni:17
    Absolute directory containing the Goma source code.

google_api_key  Default = ""
    //google_apis/BUILD.gn:45
    Set these to bake the specified API keys and OAuth client
    IDs/secrets into your build.
   
    If you create a build without values baked in, you can instead
    set environment variables to provide the keys at runtime (see
    src/google_apis/google_api_keys.h for details).  Features that
    require server-side APIs may fail to work if no keys are
    provided.
   
    Note that if you are building an official build or if
    use_official_google_api_keys has been set to trie (explicitly or
    implicitly), these values will be ignored and the official
    keys will be used instead.

google_default_client_id  Default = ""
    //google_apis/BUILD.gn:48
    See google_api_key.

google_default_client_secret  Default = ""
    //google_apis/BUILD.gn:51
    See google_api_key.

host_cpu  Default = "x64"
    (Internally set)

host_os  Default = "win"
    (Internally set)

host_toolchain  Default = ""
    //build/config/BUILDCONFIG.gn:134
    This should not normally be set as a build argument.  It's here so that
    every toolchain can pass through the "global" value via toolchain_args().

icu_use_data_file  Default = true
    //third_party/icu/config.gni:15
    Tells icu to load an external data file rather than rely on the icudata
    being linked directly into the binary.
   
    This flag is a bit confusing. As of this writing, icu.gyp set the value to
    0 but common.gypi sets the value to 1 for most platforms (and the 1 takes
    precedence).
   
    TODO(GYP) We'll probably need to enhance this logic to set the value to
    true or false in similar circumstances.

internal_gles2_conform_tests  Default = false
    //gpu/gles2_conform_support/BUILD.gn:7
    Set to true to compile with the OpenGL ES 2.0 conformance tests.

ios_use_webrtc  Default = false
    //build_overrides/webrtc.gni:19
    TODO(dpranke): This is a hack needed to get iOS to build w/ a
    patched version of WebRTC so that we can access the xmllite
    library. Remove this once we've figured out how to get WebRTC building
    properly.

is_asan  Default = false
    //build/config/sanitizers/sanitizers.gni:7
    Compile for Address Sanitizer to find memory bugs.

is_cast_desktop_build  Default = false
    //build/config/chromecast_build.gni:26
    True if Chromecast build is targeted for linux desktop. This type of build
    is useful for testing and development, but currently supports only a subset
    of Cast functionality. Though this defaults to true for x86 Linux devices,
    this should be overriden manually for an embedded x86 build.
    TODO(slan): Remove instances of this when x86 is a fully supported platform.

is_cfi  Default = false
    //build/config/sanitizers/sanitizers.gni:42
    Compile with Control Flow Integrity to protect virtual calls and casts.
    See http://clang.llvm.org/docs/ControlFlowIntegrity.html

is_chrome_branded  Default = false
    //build/config/chrome_build.gni:14
    Select the desired branding flavor. False means normal Chromium branding,
    true means official Google Chrome branding (requires extra Google-internal
    resources).

is_chromecast  Default = false
    //build/config/chromecast_build.gni:11
    Set this true for a Chromecast build. Chromecast builds are supported on
    Linux and Android.

is_clang  Default = false
    //build/config/BUILDCONFIG.gn:125
    Set to true when compiling with the Clang compiler. Typically this is used
    to configure warnings.

is_component_build  Default = false
    //build/config/BUILDCONFIG.gn:115
    Component build.

is_component_ffmpeg  Default = false
    //third_party/ffmpeg/ffmpeg_options.gni:36
    Set true to build ffmpeg as a shared library. NOTE: this means we should
    always consult is_component_ffmpeg instead of is_component_build for
    ffmpeg targets. This helps linux chromium packagers that swap out our
    ffmpeg.so with their own. See discussion here
    https://groups.google.com/a/chromium.org/forum/#!msg/chromium-packagers/R5rcZXWxBEQ/B6k0zzmJbvcJ

is_debug  Default = true
    //build/config/BUILDCONFIG.gn:118
    Debug build.

is_desktop_linux  Default = false
    //build/config/BUILDCONFIG.gn:121
    Whether we're a traditional desktop unix.

is_headless  Default = false
    //build/config/headless_build.gni:7
    Configure the build for headless mode. See crbug.com/546953.

is_lsan  Default = false
    //build/config/sanitizers/sanitizers.gni:10
    Compile for Leak Sanitizer to find leaks.

is_msan  Default = false
    //build/config/sanitizers/sanitizers.gni:13
    Compile for Memory Sanitizer to find uninitialized reads.

is_multi_dll_chrome  Default = true
    //build/config/chrome_build.gni:18
    Break chrome.dll into multple pieces based on process type. Only available
    on Windows.

is_nacl_glibc  Default = false
    //build/config/nacl/config.gni:11
    Native Client supports both Newlib and Glibc C libraries where Newlib
    is assumed to be the default one; use this to determine whether Glibc
    is being used instead.

is_official_build  Default = false
    //build/config/chrome_build.gni:9
    Selects the desired build flavor. Official builds get additional
    processing to prepare for release. Normally you will want to develop and
    test with this flag off.

is_openbsd  Default = false
    //media/media_options.gni:72
    TODO(GYP): This should be a platform define.

is_syzyasan  Default = false
    //build/config/sanitizers/sanitizers.gni:38
    Enable building with SyzyAsan which can find certain types of memory
    errors. Only works on Windows. See
    https://code.google.com/p/sawbuck/wiki/SyzyASanHowTo

is_tsan  Default = false
    //build/config/sanitizers/sanitizers.gni:16
    Compile for Thread Sanitizer to find threading bugs.

is_ubsan  Default = false
    //build/config/sanitizers/sanitizers.gni:20
    Compile for Undefined Behaviour Sanitizer to find various types of
    undefined behaviour (excludes vptr checks).

is_ubsan_vptr  Default = false
    //build/config/sanitizers/sanitizers.gni:23
    Compile for Undefined Behaviour Sanitizer's vptr checks.

is_win_fastlink  Default = false
    //build/config/win/visual_studio_version.gni:24

link_pulseaudio  Default = false
    //media/media_options.gni:13
    Allows distributions to link pulseaudio directly (DT_NEEDED) instead of
    using dlopen. This helps with automated detection of ABI mismatches and
    prevents silent errors.

linux_use_bundled_binutils  Default = false
    //build/config/compiler/BUILD.gn:35
    Whether to use the binary binutils checked into third_party/binutils.
    These are not multi-arch so cannot be used except on x86 and x86-64 (the
    only two architectures that are currently checked in). Turn this off when
    you are using a custom toolchain and need to control -B in cflags.

mac_views_browser  Default = false
    //build/config/ui.gni:39
    Whether the entire browser uses toolkit-views on Mac instead of Cocoa.

media_use_ffmpeg  Default = true
    //media/media_options.gni:18
    Enable usage of FFmpeg within the media library. Used for most software
    based decoding, demuxing, and sometimes optimized FFTs. If disabled,
    implementors must provide their own demuxers and decoders.

media_use_libvpx  Default = true
    //media/media_options.gni:22
    Enable usage of libvpx within the media library. Used for software based
    decoding of VP9 and VP8A type content.

msan_track_origins  Default = 2
    //build/config/sanitizers/sanitizers.gni:28
    Track where uninitialized memory originates from. From fastest to slowest:
    0 - no tracking, 1 - track only the initial allocation site, 2 - track the
    chain of stores leading from allocation site to use site.

msvs_xtree_patched  Default = false
    //build/config/compiler/BUILD.gn:71
    Whether the VS xtree header has been patched to disable warning 4702. If
    it has, then we don't need to disable 4702 (unreachable code warning).
    The patch is preapplied to the internal toolchain and hence all bots.

openmax_big_float_fft  Default = true
    //third_party/openmax_dl/dl/BUILD.gn:10
    Override this value to build with small float FFT tables

ozone_auto_platforms  Default = true
    //ui/ozone/ozone.gni:9
    Select platforms automatically. Turn this off for manual control.

ozone_platform  Default = "headless"
    //ui/ozone/ozone.gni:34
    Use headless as the default platform.

ozone_platform_caca  Default = false
    //ui/ozone/ozone.gni:24
    Enable individual platforms.

ozone_platform_cast  Default = false
    //ui/ozone/ozone.gni:25

ozone_platform_egltest  Default = true
    //ui/ozone/ozone.gni:61
    Build all platforms whose deps are in install-build-deps.sh.
    Only these platforms will be compile tested by buildbots.

ozone_platform_gbm  Default = false
    //ui/ozone/ozone.gni:27

ozone_platform_headless  Default = true
    //ui/ozone/ozone.gni:35

ozone_platform_ozonex  Default = false
    //ui/ozone/ozone.gni:28

ozone_platform_x11  Default = false
    //ui/ozone/ozone.gni:30

pdf_enable_v8  Default = true
    //third_party/pdfium/pdfium.gni:13
    Build PDFium either with or without v8 support.

pdf_enable_xfa  Default = false
    //third_party/pdfium/pdfium.gni:16
    Build PDFium either with or without XFA Forms support.

pdf_use_skia  Default = false
    //third_party/pdfium/pdfium.gni:19
    Build PDFium against skia (experimental) rather than agg.

pdfium_bundle_freetype  Default = true
    //third_party/pdfium/pdfium.gni:10
    On Android there's no system FreeType. On Windows and Mac, only a few
    methods are used from it.

pkg_config  Default = ""
    //build/config/linux/pkg_config.gni:33
    A pkg-config wrapper to call instead of trying to find and call the right
    pkg-config directly. Wrappers like this are common in cross-compilation
    environments.
    Leaving it blank defaults to searching PATH for 'pkg-config' and relying on
    the sysroot mechanism to find the right .pc files.

proprietary_codecs  Default = false
    //build/config/features.gni:64
    Enables proprietary codecs and demuxers; e.g. H264, MOV, AAC, and MP3.
    Android OS includes support for proprietary codecs regardless of building
    Chromium or Google Chrome. We also ship Google Chrome and Chromecast with
    proprietary codecs.

repack_whitelist  Default = ""
    //tools/grit/repack.gni:8
    Absolute path to a resource whitelist (generated using
    //tools/resources/find_used_resources.py).

root_extra_deps  Default = []
    //BUILD.gn:27
    A list of extra dependencies to add to the root target. This allows a
    checkout to add additional targets without explicitly changing any checked-
    in files.

rtc_build_expat  Default = true
    //third_party/webrtc/build/webrtc.gni:38
    Disable these to not build components which can be externally provided.

rtc_build_json  Default = true
    //third_party/webrtc/build/webrtc.gni:39

rtc_build_libjpeg  Default = true
    //third_party/webrtc/build/webrtc.gni:40

rtc_build_libvpx  Default = true
    //third_party/webrtc/build/webrtc.gni:41

rtc_build_libyuv  Default = true
    //third_party/webrtc/build/webrtc.gni:42

rtc_build_openmax_dl  Default = true
    //third_party/webrtc/build/webrtc.gni:43

rtc_build_opus  Default = true
    //third_party/webrtc/build/webrtc.gni:44

rtc_build_ssl  Default = true
    //third_party/webrtc/build/webrtc.gni:45

rtc_build_with_neon  Default = false
    //third_party/webrtc/build/webrtc.gni:87

rtc_enable_android_opensl  Default = false
    //third_party/webrtc/build/webrtc.gni:53

rtc_enable_data_logging  Default = false
    //third_party/webrtc/build/webrtc.gni:32
    Enable data logging. Produces text files with data logged within engines
    which can be easily parsed for offline processing.

rtc_enable_protobuf  Default = true
    //third_party/webrtc/build/webrtc.gni:35
    Enables the use of protocol buffers for debug recordings.

rtc_have_dbus_glib  Default = false
    //third_party/webrtc/build/webrtc.gni:48
    Disable by default.

rtc_include_opus  Default = true
    //third_party/webrtc/build/webrtc.gni:17
    Disable this to avoid building the Opus audio codec.

rtc_include_tests  Default = false
    //third_party/webrtc/build/webrtc.gni:61

rtc_jsoncpp_root  Default = "//third_party/jsoncpp/source/include"
    //third_party/webrtc/build/webrtc.gni:21
    Used to specify an external Jsoncpp include path when not compiling the
    library that comes with WebRTC (i.e. rtc_build_json == 0).

rtc_prefer_fixed_point  Default = false
    //third_party/webrtc/build/webrtc.gni:28
    Selects fixed-point code where possible.

rtc_restrict_logging  Default = true
    //third_party/webrtc/build/webrtc.gni:62

rtc_ssl_root  Default = ""
    //third_party/webrtc/build/webrtc.gni:25
    Used to specify an external OpenSSL include path when not compiling the
    library that comes with WebRTC (i.e. rtc_build_ssl == 0).

rtc_use_lto  Default = false
    //third_party/webrtc/build/webrtc.gni:58
    Link-Time Optimizations.
    Executes code generation at link-time instead of compile-time.
    https://gcc.gnu.org/wiki/LinkTimeOptimization

rtc_use_objc_h264  Default = false
    //third_party/webrtc/build/webrtc.gni:92
    Enable this to use HW H.264 encoder/decoder on iOS PeerConnections.
    Enabling this may break interop with Android clients that support H264.

rtc_use_openmax_dl  Default = true
    //third_party/webrtc/build/webrtc.gni:80

safe_browsing_mode  Default = 1
    //build/config/features.gni:109

symbol_level  Default = -1
    //build/config/compiler/compiler.gni:16
    How many symbols to include in the build. This affects the performance of
    the build since the symbols are large and dealing with them is slow.
      2 means regular build with symbols.
      1 means minimal symbols, usually enough for backtraces only.
      0 means no symbols.
      -1 means auto-set according to debug/release and platform.

system_libdir  Default = "lib"
    //build/config/linux/pkg_config.gni:44
    CrOS systemroots place pkgconfig files at <systemroot>/usr/share/pkgconfig
    and one of <systemroot>/usr/lib/pkgconfig or <systemroot>/usr/lib64/pkgconfig
    depending on whether the systemroot is for a 32 or 64 bit architecture.
   
    When build under GYP, CrOS board builds specify the 'system_libdir' variable
    as part of the GYP_DEFINES provided by the CrOS emerge build or simple
    chrome build scheme. This variable permits controlling this for GN builds
    in similar fashion by setting the `system_libdir` variable in the build's
    args.gn file to 'lib' or 'lib64' as appropriate for the target architecture.

syzygy_optimize  Default = false
    //chrome/tools/build/win/syzygy/BUILD.gn:13

target_cpu  Default = ""
    (Internally set)

target_os  Default = ""
    (Internally set)

target_sysroot  Default = ""
    //build/config/sysroot.gni:13
    The absolute path of the sysroot that is applied when compiling using
    the target toolchain.

toolkit_views  Default = true
    //build/config/ui.gni:36

treat_warnings_as_errors  Default = true
    //build/config/compiler/BUILD.gn:25
    Default to warnings as errors for default workflow, where we catch
    warnings with known toolchains. Allow overriding this e.g. for Chromium
    builds on Linux that could use a different version of the compiler.

use_allocator  Default = "none"
    //build/config/allocator.gni:16
    Memory allocator to use. Set to "none" to use default allocator.

use_alsa  Default = true
    //media/media_options.gni:43

use_ash  Default = true
    //build/config/ui.gni:23
    Indicates if Ash is enabled. Ash is the Aura Shell which provides a
    desktop-like environment for Aura. Requires use_aura = true

use_aura  Default = true
    //build/config/ui.gni:32
    Indicates if Aura is enabled. Aura is a low-level windowing library, sort
    of a replacement for GDI or GTK.

use_ccache  Default = false
    //build/toolchain/ccache.gni:24
    Set to true to enable ccache.  Probably doesn't work on windows.

use_cfi_diag  Default = false
    //build/config/sanitizers/sanitizers.gni:46
    By default, Control Flow Integrity will crash the program if it detects a
    violation. Set this to true to print detailed diagnostics instead.

use_cras  Default = false
    //media/media_options.gni:31
    Override to dynamically link the cras (ChromeOS audio) library.

use_cups  Default = false
    //build/config/features.gni:117

use_custom_libcxx  Default = false
    //build/config/sanitizers/sanitizers.gni:65

use_debug_fission  Default = "default"
    //build/config/compiler/BUILD.gn:65
    use_debug_fission: whether to use split DWARF debug info
    files. This can reduce link time significantly, but is incompatible
    with some utilities such as icecc and ccache. Requires gold and
    gcc >= 4.8 or clang.
    http://gcc.gnu.org/wiki/DebugFission
   
    This is a placeholder value indicating that the code below should set
    the default.  This is necessary to delay the evaluation of the default
    value expression until after its input values such as use_gold have
    been set, e.g. by a toolchain_args() block.

use_drfuzz  Default = false
    //build/config/sanitizers/sanitizers.gni:54
    Compile for fuzzing with Dr. Fuzz
    See http://www.chromium.org/developers/testing/dr-fuzz

use_evdev_gestures  Default = false
    //ui/events/ozone/BUILD.gn:11
    Support ChromeOS touchpad gestures with ozone.

use_glib  Default = false
    //build/config/ui.gni:48
    Whether we should use glib, a low level C utility library.

use_gold  Default = false
    //build/config/compiler/BUILD.gn:49
    TODO(GYP): We should be using 64-bit gold for linking on both 64-bit Linux
    and 32-bit linux; 32-bit Gold runs out of address-space on 32-bit builds.
    However, something isn't quite working right on the 32-bit builds.

use_goma  Default = false
    //build/toolchain/goma.gni:12
    Set to true to enable distributed compilation using Goma.

use_gtk3  Default = false
    //build/config/ui.gni:42
    Whether we should use GTKv3 instead of GTKv2.

use_libfuzzer  Default = false
    //build/config/sanitizers/sanitizers.gni:50
    Compile for fuzzing with LLVM LibFuzzer.
    See http://www.chromium.org/developers/testing/libfuzzer

use_libjpeg_turbo  Default = true
    //third_party/BUILD.gn:15
    Uses libjpeg_turbo as the jpeg implementation. Has no effect if
    use_system_libjpeg is set.

use_libpci  Default = true
    //gpu/config/BUILD.gn:10
    Use the PCI lib to collect GPU information on Linux.

use_low_memory_buffer  Default = false
    //media/media_options.gni:50
    Use low-memory buffers on non-Android builds of Chromecast.

use_official_google_api_keys  Default = ""
    //google_apis/BUILD.gn:30
    You can set the variable 'use_official_google_api_keys' to true
    to use the Google-internal file containing official API keys
    for Google Chrome even in a developer build.  Setting this
    variable explicitly to true will cause your build to fail if the
    internal file is missing.
   
    The variable is documented here, but not handled in this file;
    see //google_apis/determine_use_official_keys.gypi for the
    implementation.
   
    Set the variable to false to not use the internal file, even when
    it exists in your checkout.
   
    Leave it unset or set to "" to have the variable
    implicitly set to true if you have
    src/google_apis/internal/google_chrome_api_keys.h in your
    checkout, and implicitly set to false if not.
   
    Note that official builds always behave as if the variable
    was explicitly set to true, i.e. they always use official keys,
    and will fail to build if the internal file is missing.

use_openh264  Default = false
    //third_party/openh264/openh264_args.gni:11
    Enable this to build OpenH264 (for encoding, not decoding).
    CHECK THE OPENH264 LICENSE/PATENT BEFORE BUILDING, see
    http://www.openh264.org/.

use_openssl  Default = true
    //build/config/crypto.gni:17
    Use OpenSSL instead of NSS. This is used for all platforms but iOS. (See
    http://crbug.com/338886).

use_ozone  Default = false
    //build/config/ui.gni:28
    Indicates if Ozone is enabled. Ozone is a low-level library layer for Linux
    that does not require X11. Enabling this feature disables use of glib, x11,
    Pango, and Cairo. Default to false on non-Chromecast builds.

use_prebuilt_instrumented_libraries  Default = false
    //build/config/sanitizers/sanitizers.gni:33
    Use dynamic libraries instrumented by one of the sanitizers instead of the
    standard system libraries. Set this flag to download prebuilt binaries from
    GCS.

use_pulseaudio  Default = true
    //media/media_options.gni:45

use_sanitizer_coverage  Default = false
    //build/config/sanitizers/sanitizers.gni:67

use_srtp_boringssl  Default = true
    //third_party/libsrtp/BUILD.gn:7

use_sysroot  Default = true
    //build/config/sysroot.gni:14

use_system_harfbuzz  Default = false
    //third_party/harfbuzz-ng/BUILD.gn:23

use_system_libjpeg  Default = false
    //third_party/BUILD.gn:11
    Uses system libjpeg. If true, overrides use_libjpeg_turbo.

use_system_libsrtp  Default = false
    //third_party/libsrtp/BUILD.gn:6

use_system_sqlite  Default = false
    //third_party/sqlite/BUILD.gn:9
    Controls whether the build should uses the version of sqlite3 library
    shipped with the system (currently only supported on iOS) or the one
    shipped with Chromium source.

use_third_party_h264  Default = false
    //third_party/webrtc/build/webrtc.gni:103
    Enable this to build H.264 encoder/decoder using third party libraries.
    Encoding uses OpenH264 and decoding uses FFmpeg. Because of this, OpenH264
    and FFmpeg have to be correctly enabled separately.
    - use_openh264=true is required for OpenH264 targets to be defined.
    - ffmpeg_branding="Chrome" is one way to support H.264 decoding in FFmpeg.
      FFmpeg can be built with/without H.264 support, see 'ffmpeg_branding'.
      Without it, it compiles but H264DecoderImpl fails to initialize.
    CHECK THE OPENH264, FFMPEG AND H.264 LICENSES/PATENTS BEFORE BUILDING.
    http://www.openh264.org, https://www.ffmpeg.org/

use_unofficial_version_number  Default = true
    //components/version_info/BUILD.gn:15

use_v4l2_codec  Default = false
    //content/common/common.gni:21
    Indicates if Video4Linux2 codec is used. This is used for all CrOS
    platforms which have v4l2 hardware encoder / decoder.

use_v4lplugin  Default = false
    //content/common/common.gni:17
    Indicates if V4L plugin is used.

use_vgem_map  Default = false
    //ui/ozone/ozone.gni:16
    This enables memory-mapped access to accelerated graphics buffers via the
    VGEM ("virtual GEM") driver. This is currently only available on Chrome OS
    kernels and affects code in the GBM ozone platform.
    TODO(dshwang): remove this flag when all gbm hardware supports vgem map.
    crbug.com/519587

use_vulcanize  Default = true
    //chrome/common/features.gni:19
    Use vulcanized HTML/CSS/JS resources to speed up WebUI (chrome://)
    pages. https://github.com/polymer/vulcanize

use_xkbcommon  Default = false
    //build/config/ui.gni:45
    Optional system libraries.

v8_use_snapshot  Default = true
    //v8/BUILD.gn:23
    Enable the snapshot feature, for fast context creation.
    http://v8project.blogspot.com/2015/09/custom-startup-snapshots.html

visual_studio_path  Default = ""
    //build/config/win/visual_studio_version.gni:9
    Path to Visual Studio. If empty, the default is used which is to use the
    automatic toolchain in depot_tools. If set, you must also set the
    visual_studio_version and wdk_path.

visual_studio_version  Default = ""
    //build/config/win/visual_studio_version.gni:13
    Version of Visual Studio pointed to by the visual_studio_path.
    Use "2013" for Visual Studio 2013, or "2013e" for the Express version.

wdk_path  Default = ""
    //build/config/win/visual_studio_version.gni:17
    Directory of the Windows driver kit. If visual_studio_path is empty, this
    will be auto-filled.

win_console_app  Default = false
    //chrome/BUILD.gn:20
    If true, builds as a console app (rather than a windowed app), which allows
    logging to be printed to the user. This will cause a terminal window to pop
    up when Chrome is not run from the command line, so should only be used for
    development. Only has an effect on Windows builds.

windows_sdk_path  Default = "C:\Program Files (x86)\Windows Kits\10"
    //build/config/win/visual_studio_version.gni:22
    Full path to the Windows SDK, not including a backslash at the end.
    This value is the default location, override if you have a different
    installation location.