前言

查資料時，看到如何看gn都提供什麼引數列表了.
這樣，編譯chromium工程時，可以編譯的更精細。

實驗

可以將引數寫到 Z:\chromium\src\out\my_x86_d\args.gn 中
編譯時，執行 gn --ide=vs args out\my_x86_d
e.g.

# @file Z:\chromium\src\out\my_x86_d\args.gn
# @brief build chromium x86 release version
# @ref  https://www.chromium.org/developers/gn-build-configuration
#       https://blog.csdn.net/Vincent95/article/details/78477822
# @note 
# cd /d Z:\chromium\src\
# gn --ide=vs args out\my_x86_d
# autoninja -C out\my_x86_d chrome
# 
# 
# args.gn begin
#
target_os="win"
target_cpu = "x86"
is_component_build = true

dcheck_always_on = true
enable_nacl = false

use_goma = false
symbol_level = 2
is_debug = true
is_win_fastlink = false
remove_webcore_debug_symbols = false

# proprietary_codecs 和 media_use_ffmpeg 不相容, 只能定義一個
# proprietary_codecs = true
# media_use_ffmpeg = true
# rtc_initialize_ffmpeg = true
# rtc_use_h264 = true
# use_openh264 = true
# ffmpeg_branding = "Chrome"
#
# args.gn end
#

 

得到gn支援的全部引數列表

gn --ide=vs args out\my_x86_d --list

action_pool_depth
    Current value (from the default) = -1
      From //build/toolchain/BUILD.gn:10

    Pool for non goma tasks.

aec_untrusted_delay_for_testing
    Current value (from the default) = false
      From //third_party/webrtc/modules/audio_processing/BUILD.gn:19

    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.

allow_critical_memory_pressure_handling_in_foreground
    Current value (from the default) = false
      From //content/common/features.gni:13

    Whether to perform critical memory pressure handling when in foreground (if
    false, critical memory pressure is treated like moderate pressure in foreground).

alternate_cdm_storage_id_key
    Current value (from the default) = ""
      From //media/media_options.gni:160

    If |enable_cdm_storage_id| is set, then an implementation specific key
    must also be provided. It can be provided by defining CDM_STORAGE_ID_KEY
    (which takes precedence), or by setting |alternate_cdm_storage_id_key|.
    The key must be a string of at least 32 characters.

android_channel
    Current value (from the default) = "default"
      From //chrome/android/channel.gni:8

    The channel to build on Android: stable, beta, dev, canary, work, or
    default. "default" should be used on non-official builds.

android_full_debug
    Current value (from the default) = false
      From //build/config/compiler/BUILD.gn:47

    Normally, Android builds are lightly optimized, even for debug builds, to
    keep binary size down. Setting this flag to true disables such optimization

angle_64bit_current_cpu
    Current value (from the default) = false
      From //third_party/angle/gni/angle.gni:33

angle_enable_d3d11
    Current value (from the default) = true
      From //third_party/angle/gni/angle.gni:57

angle_enable_d3d9
    Current value (from the default) = true
      From //third_party/angle/gni/angle.gni:56

angle_enable_essl
    Current value (from the default) = true
      From //third_party/angle/gni/angle.gni:63

angle_enable_gl
    Current value (from the default) = true
      From //third_party/angle/gni/angle.gni:58

angle_enable_gl_null
    Current value (from the default) = true
      From //third_party/angle/gni/angle.gni:68

angle_enable_glsl
    Current value (from the default) = true
      From //third_party/angle/gni/angle.gni:64

angle_enable_hlsl
    Current value (from the default) = true
      From //third_party/angle/gni/angle.gni:69

angle_enable_null
    Current value (from the default) = true
      From //third_party/angle/gni/angle.gni:62

angle_enable_vulkan
    Current value (from the default) = true
      From //third_party/angle/gni/angle.gni:60

angle_enable_vulkan_validation_layers
    Current value (from the default) = true
      From //third_party/angle/gni/angle.gni:73

angle_libs_suffix
    Current value (from the default) = ""
      From //third_party/angle/gni/angle.gni:52

angle_link_glx
    Current value (from the default) = false
      From //third_party/angle/BUILD.gn:22

    Link in system libGL, to work with apitrace.  See doc/DebuggingTips.md.

angle_shared_libvulkan
    Current value (from the default) = false
      From //third_party/angle/gni/angle.gni:51

apm_debug_dump
    Current value (from the default) = false
      From //third_party/webrtc/webrtc.gni:72

    Selects whether debug dumps for the audio processing module
    should be generated.

asan_globals
    Current value (from the default) = true
      From //build/config/sanitizers/sanitizers.gni:150

    Detect overflow/underflow for global objects.
   
    Mac: http://crbug.com/352073

auto_profile_path
    Current value (from the default) = ""
      From //build/config/compiler/BUILD.gn:91

    AFDO (Automatic Feedback Directed Optimizer) is a form of profile-guided
    optimization that GCC supports. It used by ChromeOS in their official
    builds. To use it, set auto_profile_path to the path to a file containing
    the needed gcov profiling data.

binutils_path
    Current value (from the default) = "../../third_party/binutils/Linux_x64/Release/bin"
      From //build/config/compiler/BUILD.gn:56

blink_gc_plugin
    Current value (from the default) = true
      From //third_party/blink/renderer/BUILD.gn:17

    Set to true to enable the clang plugin that checks the usage of the  Blink
    garbage-collection infrastructure during compilation.

blink_gc_plugin_option_do_dump_graph
    Current value (from the default) = false
      From //third_party/blink/renderer/BUILD.gn:21

    Set to true to have the clang Blink GC plugin emit class graph (in JSON)
    with typed pointer edges; for debugging or other (internal) uses.

blink_gc_plugin_option_warn_trace_wrappers_missing_base_dispatch
    Current value (from the default) = false
      From //third_party/blink/renderer/BUILD.gn:30

    Set to true to have the clang Blink GC plugin additionally check if a
    TraceWrappers method also dispatches to all its base classes.

blink_gc_plugin_option_warn_unneeded_finalizer
    Current value (from the default) = false
      From //third_party/blink/renderer/BUILD.gn:26

    Set to true to have the clang Blink GC plugin additionally check if
    a class has an empty destructor which would be unnecessarily invoked
    when finalized.

blink_symbol_level
    Current value (from the default) = -1
      From //third_party/blink/renderer/config.gni:32

    How many symbols to include in the build of blink. 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. Symbols with
    internal linkage (static functions or those in anonymous namespaces) may not
    appear when using this level.
      0 means no symbols.
      -1 means auto-set according to debug/release and platform.

build_angle_deqp_tests
    Current value (from the default) = false
      From //third_party/angle/src/tests/BUILD.gn:19

    Don't build dEQP by default.

build_angle_gles1_conform_tests
    Current value (from the default) = false
      From //third_party/angle/src/tests/BUILD.gn:20

build_devil_arm_deps
    Current value (from the default) = false
      From //build/secondary/third_party/catapult/devil/devil_arm.gni:8

    Whether to build Devil host dependencies for Linux arm, e.g. for use on
    Raspberry Pis.

build_display_configuration
    Current value (from the default) = false
      From //ui/display/display.gni:7

    Build Chrome OS display configuration code.

build_libsrtp_tests
    Current value (from the default) = false
      From //third_party/libsrtp/BUILD.gn:10

    Tests may not be appropriate for some build environments, e.g. Windows.
    Rather than enumerate valid options, we just let clients ask for them.

build_sfntly_samples
    Current value (from the default) = false
      From //third_party/sfntly/BUILD.gn:9

    Flip to true to build sfntly sample programs.

build_with_mozilla
    Current value (from the default) = false
      From //third_party/webrtc/webrtc.gni:87

    Enable to use the Mozilla internal settings.

cc_wrapper
    Current value (from the default) = ""
      From //build/toolchain/cc_wrapper.gni:36

    Set to "ccache", "icecc" or "distcc".  Probably doesn't work on windows.

chrome_pgo_phase
    Current value (from the default) = 0
      From //build/config/compiler/pgo/pgo.gni:13

    Specify the current PGO phase.
    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.

clang_base_path
    Current value (from the default) = "//third_party/llvm-build/Release+Asserts"
      From //build/config/clang/clang.gni:14

clang_sample_profile_path
    Current value (from the default) = ""
      From //build/config/compiler/BUILD.gn:112

    Path to an AFDO profile to use while building with clang, if any. Empty
    implies none.

clang_use_chrome_plugins
    Current value (from the default) = true
      From //build/config/clang/clang.gni:12

    Indicates if the build should use the Chrome-specific plugins for enforcing
    coding guidelines, etc. Only used when compiling with Clang.

clang_use_default_sample_profile
    Current value (from the default) = false
      From //build/config/compiler/BUILD.gn:120

    Some configurations have default sample profiles. If this is true and
    clang_sample_profile_path is empty, we'll fall back to the default.
   
    We currently only have default profiles for Chromium in-tree, so we disable
    this by default for all downstream projects, since these profiles are likely
    nonsensical for said projects.

clang_version
    Current value (from the default) = "7.0.0"
      From //build/toolchain/toolchain.gni:51

    Clang compiler version. Clang files are placed at version-dependent paths.

closure_compile
    Current value (from the default) = false
      From //ui/webui/webui_features.gni:14

    Enable closure type-checking for Chrome's web technology-based UI. This
    enables the webui_closure_compile target which does a no-op without this
    flag enabled. Requires Java.

com_init_check_hook_disabled
    Current value (from the default) = false
      From //base/BUILD.gn:52

    Set to true to disable COM init check hooks.

compiler_timing
    Current value (from the default) = false
      From //build/config/compiler/BUILD.gn:124

    Turn this on to have the compiler output extra timing information.

compute_grit_inputs_for_analyze
    Current value (from the default) = false
      From //tools/grit/grit_rule.gni:106

    When set, this will fork out to grit at GN-time to get all inputs
    referenced by the .grd file.
   
    Normal builds don't need this since proper incremental builds are handled
    by grit writing out the inputs in .d files at build-time. But for analyze
    to work on the bots, it needs to know about all input files at GN-time so
    it knows which tests to trigger when something changes. This option will
    slow down the GN run.

concurrent_links
    Current value (from the default) = -1
      From //build/toolchain/concurrent_links.gni:19

    Limit the number of concurrent links; we often want to run fewer
    links at once than we do compiles, because linking is memory-intensive.
    The default to use varies by platform and by the amount of memory
    available, so we call out to a script to get the right value.

content_shell_product_name
    Current value (from the default) = "Content Shell"
      From //content/shell/BUILD.gn:28

content_shell_version
    Current value (from the default) = "99.77.34.5"
      From //content/shell/BUILD.gn:29

crashpad_dependencies
    Current value = "chromium"
      From //.gn:69
    Overridden from the default = "standalone"
      From //third_party/crashpad/crashpad/build/crashpad_buildconfig.gni:19

    Determines various flavors of build configuration, and which concrete
    targets to use for dependencies. Valid values are "standalone", "chromium",
    and "fuchsia".

current_cpu
    Current value (from the default) = ""
      (Internally set; try `gn help current_cpu`.)

current_os
    Current value (from the default) = ""
      (Internally set; try `gn help current_os`.)

custom_toolchain
    Current value (from the default) = ""
      From //build/config/BUILDCONFIG.gn:144

    Allows the path to a custom target toolchain to be injected as a single
    argument, and set as the default toolchain.

dcheck_always_on
    Current value = true
      From //out/my_x86_d/args.gn:17
    Overridden from the default = false
      From //build/config/dcheck_always_on.gni:14

    Set to true to enable dcheck in Release builds.

dcheck_is_configurable
    Current value (from the default) = false
      From //build/config/dcheck_always_on.gni:9

    Enables DCHECKs to be built-in, but to default to being non-fatal/log-only.
    DCHECKS can then be set as fatal/non-fatal via the DCheckIsFatal feature.
    See crbug.com/596231 for details on how this is used.

debug_devtools
    Current value (from the default) = false
      From //third_party/blink/public/public_features.gni:12

    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_brotli_filter
    Current value (from the default) = false
      From //net/features.gni:27

    Do not disable brotli filter by default.

disable_file_support
    Current value (from the default) = false
      From //net/features.gni:12

    Disables support for file URLs.  File URL support requires use of icu.

disable_ftp_support
    Current value (from the default) = false
      From //net/features.gni:17

disable_libfuzzer
    Current value (from the default) = false
      From //build/config/sanitizers/sanitizers.gni:91

    Helper variable for testing builds with disabled libfuzzer.
    Not for client use.

enable_ac3_eac3_audio_demuxing
    Current value (from the default) = false
      From //media/media_options.gni:56

    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
    Current value (from the default) = false
      From //chrome/common/features.gni:23

enable_app_shell_installer
    Current value (from the default) = false
      From //extensions/shell/installer/BUILD.gn:15

enable_arcore
    Current value (from the default) = false
      From //device/vr/buildflags/buildflags.gni:44

    TODO(crbug.com/841389): We should eventually have a single flag for
    enabling arcore, but we currently don't support ARCore in 64bit, and we do
    not support all channels. This flag governs the inclusion of code that must
    be identical across configs.

enable_av1_decoder
    Current value (from the default) = false
      From //third_party/libaom/options.gni:5

    Enable decoding AV1 video files.

enable_background_contents
    Current value (from the default) = true
      From //chrome/common/features.gni:26

    Enables support for background apps.

enable_background_mode
    Current value (from the default) = true
      From //chrome/common/features.gni:27

enable_basic_print_dialog
    Current value (from the default) = true
      From //chrome/common/features.gni:31

    Enable the printing system dialog for platforms that support printing
    and have a system dialog.

enable_basic_printing
    Current value (from the default) = true
      From //printing/buildflags/buildflags.gni:10

    Enable basic printing support and UI.

enable_blink_heap_incremental_marking
    Current value (from the default) = true
      From //third_party/blink/renderer/platform/heap/BUILD.gn:15

    Build Blink with incremental marking infrastructure for Oilpan.
   
    To turn on incremental marking also use
      --enable-blink-features=HeapIncrementalMarking

enable_blink_heap_verification
    Current value (from the default) = false
      From //third_party/blink/renderer/platform/heap/BUILD.gn:18

    Enables heap verification.

enable_callgrind
    Current value (from the default) = false
      From //third_party/pdfium/pdfium.gni:54

    Enable callgrind for performance profiling

enable_captive_portal_detection
    Current value (from the default) = true
      From //chrome/common/features.gni:33

enable_cbcs_encryption_scheme
    Current value (from the default) = true
      From //media/media_options.gni:65

    Enable parsing for the 'cbcs' encryption scheme added by MPEG Common
    Encryption 3rd Edition (ISO/IEC 23001-7), published 02/15/2016.

enable_cdm_host_verification
    Current value (from the default) = false
      From //media/media_options.gni:149

enable_cdm_storage_id
    Current value (from the default) = false
      From //media/media_options.gni:153

    Enable Storage ID which is used by CDMs. This is only available with chrome
    branding, but may be overridden by other embedders.

enable_cros_assistant
    Current value (from the default) = false
      From //chromeos/assistant/assistant.gni:4

    Enable assistant features. Assistant related code is compiled only when
    true. The default assistant implementation is a stub.

enable_cros_libassistant
    Current value (from the default) = false
      From //chromeos/assistant/assistant.gni:8

    Enable assistant implementation based on libassistant. This requires
    enable_cros_assistant also enabled.

enable_cros_libassistant_so
    Current value (from the default) = false
      From //chromeos/assistant/assistant.gni:12

    Enable building libassistant.so shared library from local checkout. This is
    for development purposes only.

enable_debugallocation
    Current value (from the default) = true
      From //base/allocator/BUILD.gn:13

    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_desktop_in_product_help
    Current value (from the default) = true
      From //components/feature_engagement/features.gni:9

    In-Product Help is only available in Windows and Linux OS for
    desktop. Other platforms such as Mac OS currently does not support
    Views and there have been no strong feelings about CrOS.

enable_dolby_vision_demuxing
    Current value (from the default) = false
      From //media/media_options.gni:74

    Enable Dolby Vision demuxing. Enable by default for Chromecast. Actual
    decoding must be provided by the platform. Note some Dolby Vision profiles
    which are encoded using HEVC require |enable_hevc_demuxing| to be enabled.

enable_extensions
    Current value (from the default) = true
      From //extensions/buildflags/buildflags.gni:8

enable_feed_in_chrome
    Current value (from the default) = false
      From //components/feed/features.gni:6

enable_ffmpeg_video_decoders
    Current value (from the default) = true
      From //media/media_options.gni:118

    On Android, FFMpeg is built without video decoders by default.
    This flag gives the option to override that decision in case there are no
    hardware decoders. To do so, you will also need to update ffmpeg build files
    in order to define which decoders to build in.

enable_full_stack_frames_for_profiling
    Current value (from the default) = false
      From //build/config/compiler/BUILD.gn:64

    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
    Current value (from the default) = false
      From //chrome/common/features.gni:37

    Google Now is disabled to prepare for its removal.
    http://crbug.com/539674

enable_gvr_services
    Current value (from the default) = false
      From //device/vr/buildflags/buildflags.gni:13

    TODO(733935): Enable for other Android architectures too. Currently we only
    support arm and arm64.

enable_hangout_services_extension
    Current value (from the default) = false
      From //chrome/common/features.gni:41

    Hangout services is an extension that adds extra features to Hangouts.
    It is enableable separately to facilitate testing.

enable_hevc_demuxing
    Current value (from the default) = false
      From //media/media_options.gni:69

    Enable HEVC/H265 demuxing. Actual decoding must be provided by the
    platform. Enable by default for Chromecast.

enable_hls_sample_aes
    Current value (from the default) = false
      From //media/media_options.gni:77

    Enable HLS with SAMPLE-AES decryption.

enable_internal_app_remoting_targets
    Current value (from the default) = false
      From //remoting/remoting_options.gni:18

    Set this to enable building internal AppRemoting apps.

enable_ipc_fuzzer
    Current value (from the default) = false
      From //tools/ipc_fuzzer/ipc_fuzzer.gni:15

enable_ipc_logging
    Current value (from the default) = true
      From //ipc/features.gni:7

    Enabling debug builds automatically sets enable_ipc_logging to true.

enable_iterator_debugging
    Current value (from the default) = true
      From //build/config/BUILD.gn:36

    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_linux_installer
    Current value (from the default) = false
      From //chrome/installer/BUILD.gn:11

enable_location_source
    Current value (from the default) = true
      From //base/BUILD.gn:44

    Indicates if the Location object contains the source code information
    (file, function, line). False means only the program counter (and currently
    file name) is saved.

enable_mdns
    Current value (from the default) = true
      From //net/features.gni:30

    Multicast DNS.

enable_media_remoting
    Current value (from the default) = true
      From //media/media_options.gni:241

    This switch defines whether the Media Remoting implementation will be built.
    When enabled, media is allowed to be renderer and played back on remote
    devices when the tab is being casted and other conditions are met.

enable_media_remoting_rpc
    Current value (from the default) = true
      From //media/media_options.gni:247

    Media Remoting RPC is disabled on Android since it's unused but increases
    the native binary size by ~70Kb.

enable_media_router_jscompile
    Current value (from the default) = false
      From //chrome/browser/resources/media_router/extension/BUILD.gn:12

    Determines whether JSCompiler should be used to typecheck
    JavaScript code for the Media Router extension.

enable_message_center
    Current value (from the default) = true
      From //ui/base/ui_features.gni:18

    Whether the message center should be included for displaying notifications.

enable_mojo_media
    Current value (from the default) = true
      From //media/media_options.gni:132

enable_mojo_tracing
    Current value (from the default) = false
      From //mojo/public/cpp/bindings/BUILD.gn:7

enable_mojom_message_id_scrambling
    Current value (from the default) = true
      From //mojo/public/tools/bindings/mojom.gni:33

    Controls message ID scrambling behavior. If |true|, message IDs are
    scrambled (i.e. randomized based on the contents of //chrome/VERSION) on
    non-Chrome OS desktop platforms. Set to |false| to disable message ID
    scrambling on all platforms.

enable_mojom_typemapping
    Current value (from the default) = true
      From //mojo/public/tools/bindings/mojom.gni:27

    Indicates whether typemapping should be supported in this build
    configuration. This may be disabled when building external projects which
    depend on //mojo but which do not need/want all of the Chromium tree
    dependencies that come with typemapping.
   
    Note that (perhaps obviously) a huge amount of Chromium code will not build
    with typemapping disabled, so it is never valid to set this to |false| in
    any Chromium build configuration.

enable_mpeg_h_audio_demuxing
    Current value (from the default) = false
      From //media/media_options.gni:58

enable_mse_mpeg2ts_stream_parser
    Current value (from the default) = false
      From //media/media_options.gni:61

enable_mus
    Current value (from the default) = false
      From //ui/base/ui_features.gni:21

    Set to true to if mus (aka the window service) is enabled.

enable_mutex_priority_inheritance
    Current value (from the default) = false
      From //base/BUILD.gn:57

    Set to true to enable mutex priority inheritance. See the comments in
    LockImpl::PriorityInheritanceAvailable() in lock_impl_posix.cc for the
    platform requirements to safely enable priority inheritance.

enable_nacl
    Current value = false
      From //out/my_x86_d/args.gn:18
    Overridden from the default = true
      From //components/nacl/features.gni:13

enable_nacl_nonsfi
    Current value (from the default) = true
      From //components/nacl/features.gni:18

    Non-SFI is not yet supported on mipsel

enable_native_notifications
    Current value (from the default) = true
      From //chrome/common/features.gni:44

    Enables usage of the system-provided notification center.

enable_native_window_nav_buttons
    Current value (from the default) = false
      From //ui/views/features.gni:12

enable_net_mojo
    Current value (from the default) = true
      From //net/features.gni:45

enable_nocompile_tests
    Current value (from the default) = false
      From //build/nocompile.gni:63

enable_oculus_vr
    Current value (from the default) = false
      From //device/vr/buildflags/buildflags.gni:20

    To build with Oculus support, the Oculus SDK for Windows will need to be
    installed in third_party/libovr/src.  See
    third_party/libovr/README.chromium for details.

enable_offline_pages
    Current value (from the default) = false
      From //components/offline_pages/buildflags/features.gni:8

    Whether to enable OfflinePages support. Currently user-visible features
    are Android-only.

enable_offline_pages_harness
    Current value (from the default) = false
      From //components/offline_pages/buildflags/features.gni:12

    This enables test API for locally-built harness which is used for quality
    evaluations. Requires setting this variable manually at local environment.

enable_one_click_signin
    Current value (from the default) = true
      From //chrome/common/features.gni:48

enable_openvr
    Current value (from the default) = true
      From //device/vr/buildflags/buildflags.gni:15

enable_pdf
    Current value (from the default) = true
      From //pdf/features.gni:12

enable_plugins
    Current value (from the default) = true
      From //ppapi/buildflags/buildflags.gni:10

enable_precompiled_headers
    Current value (from the default) = true
      From //build/config/pch.gni:11

    Precompiled header file support is by default available,
    but for distributed build system uses (like goma) or when
    doing official builds.

enable_print_preview
    Current value (from the default) = true
      From //printing/buildflags/buildflags.gni:16

    Enable printing with print preview. It implies enable_basic_printing.
    Note: It would be convenient to not repeat many of the same conditions in
    enable_basic_printing below. However, GN does not allow the use of
    enable_basic_printing within the same declare_args() block.

enable_profiling
    Current value (from the default) = false
      From //build/config/compiler/compiler.gni:30

    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_reading_list
    Current value (from the default) = true
      From //components/reading_list/features/reading_list.gni:8

    Controls whether reading list support is active or not. Currently only
    supported on iOS (on other platforms, the feature is always disabled).

enable_remoting
    Current value (from the default) = true
      From //remoting/remoting_enable.gni:12

enable_remoting_jscompile
    Current value (from the default) = false
      From //remoting/remoting_options.gni:15

    Set this to run the jscompile checks after building the webapp.

enable_reporting
    Current value (from the default) = true
      From //net/features.gni:33

    Reporting not used on iOS.

enable_resource_whitelist_generation
    Current value (from the default) = false
      From //build/config/android/config.gni:373

    Enables used resource whitelist generation. Set for official builds only
    as a large amount of build output is generated.

enable_runtime_media_renderer_selection
    Current value (from the default) = false
      From //media/media_options.gni:144

    When enabled, this feature allows developers to use a runtime flag to
    choose the implementation of the renderer that is used. On a build which
    enables the mojo renderer, if --disable-mojo-renderer is passed at start-up,
    the "default" renderer will be used instead. Both renderer implementations
    will be linked if this feature is enabled, increasing the binary size. This
    feature does not make sense if the mojo renderer is not enabled.

enable_service_discovery
    Current value (from the default) = true
      From //chrome/common/features.gni:50

enable_session_service
    Current value (from the default) = true
      From //chrome/common/features.gni:54

    Enables use of the session service, which is enabled by default.
    Android stores them separately on the Java side.

enable_supervised_users
    Current value (from the default) = true
      From //chrome/common/features.gni:56

enable_swiftshader
    Current value (from the default) = true
      From //ui/gl/BUILD.gn:15

enable_test_mojo_media_client
    Current value (from the default) = false
      From //media/media_options.gni:136

    Enable the TestMojoMediaClient to be used in mojo MediaService. This is for
    testing only and will override the default platform MojoMediaClient, if any.

enable_vr
    Current value (from the default) = true
      From //device/vr/buildflags/buildflags.gni:28

enable_vulkan
    Current value (from the default) = false
      From //gpu/vulkan/features.gni:9

    Enable experimental vulkan backend.

enable_wayland_server
    Current value (from the default) = false
      From //chrome/common/features.gni:59

    Indicates if Wayland display server support is enabled.

enable_websockets
    Current value (from the default) = true
      From //net/features.gni:16

    WebSockets and socket stream code are not used on iOS and are optional in
    cronet.

enable_widevine
    Current value (from the default) = false
      From //third_party/widevine/cdm/widevine.gni:10

    Allow Widevine key system support in Chromium.

enable_wifi_display
    Current value (from the default) = false
      From //extensions/buildflags/buildflags.gni:12

    Enables Wi-Fi Display functionality
    WARNING: This enables MPEG Transport Stream (MPEG-TS) encoding!

fatal_linker_warnings
    Current value (from the default) = true
      From //build/config/compiler/BUILD.gn:80

    Enable fatal linker warnings. Building Chromium with certain versions
    of binutils can cause linker warning.
    See: https://bugs.chromium.org/p/chromium/issues/detail?id=457359

ffmpeg_branding
    Current value (from the default) = "Chromium"
      From //third_party/ffmpeg/ffmpeg_options.gni:34

    Controls whether we build the Chromium or Google Chrome version of FFmpeg.
    The Google Chrome version contains additional codecs. Typical values are
    Chromium, Chrome, and ChromeOS.

ffmpeg_use_atomics_fallback
    Current value (from the default) = false
      From //third_party/ffmpeg/ffmpeg_options.gni:51

    Set to true to force the use of ffmpeg's stdatomic fallback code.
   
    Windows and GCC prior to 4.9 lack stdatomic.h.
   
    This is also useful for developers who use icecc, which relies upon
    clang's -frewrite-includes flag which is broken with #include_next
    directives as used in chromium's clang stdatomic.h.
    Some background: https://bugs.llvm.org/show_bug.cgi?id=26828

fieldtrial_testing_like_official_build
    Current value (from the default) = false
      From //build/config/features.gni:46

    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.

full_wpo_on_official
    Current value (from the default) = false
      From //build/config/compiler/compiler.gni:156

generate_linker_map
    Current value (from the default) = false
      From //build/toolchain/toolchain.gni:28

    Used for binary size analysis.
    Currently disabled on LLD because of a bug (fixed upstream).
    See https://crbug.com/716209.

generate_order_files
    Current value (from the default) = false
      From //build/config/chrome_build.gni:17

    Turn this on to generate order files. See
    https://chromium.googlesource.com/chromium/src/+/master/docs/win_order_files.md

gold_path
    Current value (from the default) = false
      From //build/config/compiler/BUILD.gn:68

    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
    Current value (from the default) = "C:\src\goma\goma-win64"
      From //build/toolchain/goma.gni:14

    Absolute directory containing the gomacc.exe binary.

google_api_key
    Current value (from the default) = ""
      From //google_apis/BUILD.gn:46

    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
    Current value (from the default) = ""
      From //google_apis/BUILD.gn:49

    See google_api_key.

google_default_client_secret
    Current value (from the default) = ""
      From //google_apis/BUILD.gn:52

    See google_api_key.

has_native_accessibility
    Current value (from the default) = true
      From //ui/base/ui_features.gni:15

    Whether the platform provides a native accessibility toolkit.

headless_fontconfig_utils
    Current value (from the default) = false
      From //headless/headless.gni:10

    Provide bindings for font loading for headless embedders.

headless_use_embedded_resources
    Current value (from the default) = false
      From //headless/headless.gni:7

    Embed resource.pak file into the binary for easier distribution.

host_byteorder
    Current value (from the default) = "undefined"
      From //build/config/host_byteorder.gni:9

host_cpu
    Current value (from the default) = "x64"
      (Internally set; try `gn help host_cpu`.)

host_os
    Current value (from the default) = "win"
      (Internally set; try `gn help host_os`.)

host_pkg_config
    Current value (from the default) = ""
      From //build/config/linux/pkg_config.gni:36

    A optional pkg-config wrapper to use for tools built on the host.

host_toolchain
    Current value (from the default) = ""
      From //build/config/BUILDCONFIG.gn:148

    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
    Current value (from the default) = true
      From //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.

ignore_elf32_limitations
    Current value (from the default) = false
      From //build_overrides/build.gni:41

    Android 32-bit non-component, non-clang builds cannot have symbol_level=2
    due to 4GiB file size limit, see https://crbug.com/648948.
    Set this flag to true to skip the assertion.

include_transport_security_state_preload_list
    Current value (from the default) = true
      From //net/features.gni:41

    Includes the transport security state preload list. This list includes
    mechanisms (e.g. HSTS, HPKP) to enforce trusted connections to a significant
    set of hardcoded domains. While this list has a several hundred KB of binary
    size footprint, this flag should not be disabled unless the embedder is
    willing to take the responsibility to make sure that all important
    connections use HTTPS.

include_vr_data
    Current value (from the default) = false
      From //device/vr/buildflags/buildflags.gni:32

    Whether to include VR extras like test APKs in non-VR-specific targets

internal_gles2_conform_tests
    Current value (from the default) = false
      From //gpu/gles2_conform_support/BUILD.gn:7

    Set to true to compile with the OpenGL ES 2.0 conformance tests.

internal_khronos_glcts_tests
    Current value (from the default) = false
      From //gpu/khronos_glcts_support/BUILD.gn:8

ios_deployment_target
    Current value (from the default) = "10.0"
      From //build/config/ios/ios_sdk_overrides.gni:10

    Version of iOS that we're targeting.

is_asan
    Current value (from the default) = false
      From //build/config/sanitizers/sanitizers.gni:11

    Compile for Address Sanitizer to find memory bugs.

is_cast_audio_only
    Current value (from the default) = false
      From //build/config/chromecast_build.gni:14

    Set this true for an audio-only Chromecast build.

is_cast_desktop_build
    Current value (from the default) = false
      From //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_cast_using_cma_backend
    Current value (from the default) = true
      From //media/media_options.gni:80

    If true, use cast CMA backend instead of default chromium media pipeline.

is_cfi
    Current value (from the default) = false
      From //build/config/sanitizers/sanitizers.gni:53

    Compile with Control Flow Integrity to protect virtual calls and casts.
    See http://clang.llvm.org/docs/ControlFlowIntegrity.html
   
    TODO(pcc): Remove this flag if/when CFI is enabled in all official builds.

is_chrome_branded
    Current value (from the default) = false
      From //build/config/chrome_build.gni:9

    Select the desired branding flavor. False means normal Chromium branding,
    true means official Google Chrome branding (requires extra Google-internal
    resources).

is_chromecast
    Current value (from the default) = false
      From //build/config/chromecast_build.gni:11

    Set this true for a Chromecast build. Chromecast builds are supported on
    Linux and Android.

is_clang
    Current value (from the default) = true
      From //build/config/BUILDCONFIG.gn:137

    Set to true when compiling with the Clang compiler.

is_component_build
    Current value = true
      From //out/my_x86_d/args.gn:15
    Overridden from the default = true
      From //build/config/BUILDCONFIG.gn:165

    Component build. Setting to true compiles targets declared as "components"
    as shared libraries loaded dynamically. This speeds up development time.
    When false, components will be linked statically.
   
    For more information see
    https://chromium.googlesource.com/chromium/src/+/master/docs/component_build.md

is_component_ffmpeg
    Current value (from the default) = true
      From //third_party/ffmpeg/ffmpeg_options.gni:41

    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
    Current value = true
      From //out/my_x86_d/args.gn:22
    Overridden from the default = true
      From //build/config/BUILDCONFIG.gn:155

    Debug build. Enabling official builds automatically sets is_debug to false.

is_desktop_linux
    Current value (from the default) = false
      From //build/config/BUILDCONFIG.gn:134

    Whether we're a traditional desktop unix.

is_lsan
    Current value (from the default) = false
      From //build/config/sanitizers/sanitizers.gni:14

    Compile for Leak Sanitizer to find leaks.

is_msan
    Current value (from the default) = false
      From //build/config/sanitizers/sanitizers.gni:17

    Compile for Memory Sanitizer to find uninitialized reads.

is_multi_dll_chrome
    Current value (from the default) = false
      From //build/config/chrome_build.gni:13

    Break chrome.dll into multple pieces based on process type. Only available
    on Windows.

is_nacl_glibc
    Current value (from the default) = false
      From //build/config/nacl/config.gni:9

    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
    Current value (from the default) = false
      From //build/config/BUILDCONFIG.gn:131

    Set to enable the official build level of optimization. This has nothing
    to do with branding, but enables an additional level of optimization above
    release (!is_debug). This might be better expressed as a tri-state
    (debug, release, official) but for historical reasons there are two
    separate flags.

is_proto_quic
    Current value (from the default) = false
      From //net/features.gni:9

    If true, prune things down as needed for proto-quic build.

is_tsan
    Current value (from the default) = false
      From //build/config/sanitizers/sanitizers.gni:20

    Compile for Thread Sanitizer to find threading bugs.

is_ubsan
    Current value (from the default) = false
      From //build/config/sanitizers/sanitizers.gni:24

    Compile for Undefined Behaviour Sanitizer to find various types of
    undefined behaviour (excludes vptr checks).

is_ubsan_no_recover
    Current value (from the default) = false
      From //build/config/sanitizers/sanitizers.gni:27

    Halt the program if a problem is detected.

is_ubsan_null
    Current value (from the default) = false
      From //build/config/sanitizers/sanitizers.gni:30

    Compile for Undefined Behaviour Sanitizer's null pointer checks.

is_ubsan_security
    Current value (from the default) = false
      From //build/config/sanitizers/sanitizers.gni:83

    Enables core ubsan security features. Will later be removed once it matches
    is_ubsan.

is_ubsan_vptr
    Current value (from the default) = false
      From //build/config/sanitizers/sanitizers.gni:33

    Compile for Undefined Behaviour Sanitizer's vptr checks.

is_unsafe_developer_build
    Current value (from the default) = true
      From //base/BUILD.gn:49

    Unsafe developer build. Has developer-friendly features that may weaken or
    disable security measures like sandboxing or ASLR.
    IMPORTANT: Unsafe developer builds should never be distributed to end users.

is_win_fastlink
    Current value = false
      From //out/my_x86_d/args.gn:23
    Overridden from the default = false
      From //build/config/compiler/compiler.gni:51

    Tell VS to create a PDB that references information in .obj files rather
    than copying it all. This should improve linker performance. mspdbcmf.exe
    can be used to convert a fastlink pdb to a normal one.

jumbo_build_excluded
    Current value (from the default) = []
      From //build/config/jumbo.gni:15

    A list of targets to exclude from jumbo builds, for optimal round trip time
    when frequently changing a set of cpp files.

jumbo_file_merge_limit
    Current value (from the default) = -1
      From //build/config/jumbo.gni:31

    How many files to group at most. Smaller numbers give more
    parallellism, higher numbers give less total CPU usage. Higher
    numbers also give longer single-file recompilation times.
   
    Recommendations:
    Higher numbers than 100 does not reduce wall clock compile times
    even for 4 cores or less so no reason to go higher than 100.
    Going from 50 to 100 with a 4 core CPU saves about 3% CPU time and
    3% wall clock time in a tree with blink, v8 and content
    jumbofied. At the same time it increases the compile time for the
    largest jumbo chunks by 10-20% and reduces the chance to use all
    available CPU cores. So set the default to 50 to balance between
    high and low-core build performance. -1 means do the default which
    varies depending on whether goma is enabled.

libcpp_is_static
    Current value (from the default) = false
      From //build/config/c++/c++.gni:33

    ASan, MSan and TSan builds need to override operator new, operator delete,
    and some exception handling symbols, so libc++ must be a shared library to
    prevent duplicate symbol errors when linking.
    Additionally, -fsanitize=vptr requires libc++ to be a shared library
    because the ubsan runtime library that implements -fsanitize=vptr calls
    dynamic_cast with the ABI type info classes, which won't return the right
    answer if each DSO has its own copy of the ABI classes.

libyuv_disable_jpeg
    Current value (from the default) = false
      From //third_party/libyuv/libyuv.gni:15

libyuv_include_tests
    Current value (from the default) = false
      From //third_party/libyuv/libyuv.gni:14

libyuv_symbols_visible
    Current value (from the default) = false
      From //third_party/libyuv/BUILD.gn:19

    When building a shared library using a target in WebRTC or
    Chromium projects that depends on libyuv, setting this flag
    to true makes libyuv symbols visible inside that library.

libyuv_use_gflags
    Current value (from the default) = true
      From //third_party/libyuv/BUILD.gn:14

    Set to false to disable building with gflags.

libyuv_use_msa
    Current value (from the default) = false
      From //third_party/libyuv/libyuv.gni:18

libyuv_use_neon
    Current value (from the default) = false
      From //third_party/libyuv/libyuv.gni:16

link_pulseaudio
    Current value (from the default) = false
      From //media/media_options.gni:33

    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
    Current value (from the default) = false
      From //build/config/compiler/BUILD.gn:54

llvm_force_head_revision
    Current value (from the default) = false
      From //build/toolchain/toolchain.gni:18

    If this is set to true, or if LLVM_FORCE_HEAD_REVISION is set to 1
    in the environment, we use the revision in the llvm repo to determine
    the CLANG_REVISION to use, instead of the version hard-coded into
    //tools/clang/scripts/update.py. This should only be used in
    conjunction with setting LLVM_FORCE_HEAD_REVISION in the
    environment when `gclient runhooks` is run as well.

mac_sdk_min
    Current value (from the default) = "10.12"
      From //build/config/mac/mac_sdk_overrides.gni:12

mac_views_browser
    Current value (from the default) = false
      From //ui/base/ui_features.gni:12

    Whether the entire browser uses toolkit-views on Mac instead of Cocoa.

media_use_ffmpeg
    Current value (from the default) = true
      From //media/media_options.gni:38

    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
    Current value (from the default) = true
      From //media/media_options.gni:42

    Enable usage of libvpx within the media library. Used for software based
    decoding of VP9 and VP8A type content.

mojo_media_host
    Current value (from the default) = "none"
      From //media/media_options.gni:198

    The process that the mojo MediaService runs in. By default, all services
    registered in |mojo_media_services| are hosted in the MediaService, with the
    exception that when |enable_library_cdms| is true, the "cdm" service will
    run in a separate CdmService in the CDM (utility) process, while other
    |mojo_media_services| still run in the MediaService in the process specified
    by "mojo_media_host".
    Valid options are:
    - "none": Do not use mojo media service.
    - "browser": Use mojo media service hosted in the browser process.
    - "gpu": Use mojo media service hosted in the gpu process.
    - "utility": Use mojo media service hosted in the utility process.

mojo_media_services
    Current value (from the default) = []
      From //media/media_options.gni:185

    A list of mojo media services that should be used in the media pipeline.
    Must not be empty if |enable_mojo_media| is true.
    Valid entries in the list are:
    - "renderer": Use mojo-based media Renderer service.
    - "cdm": Use mojo-based Content Decryption Module.
    - "audio_decoder": Use mojo-based audio decoder in the default media
                       Renderer. Cannot be used with the mojo Renderer above.
    - "video_decoder": Use mojo-based video decoder in the default media
                       Renderer. Cannot be used with the mojo Renderer above.

mojom_message_id_salt_path
    Current value (from the default) = "//chrome/VERSION"
      From //mojo/public/tools/bindings/mojom.gni:80

    The path to a file whose contents can be used as the basis for a message
    ID scrambling salt.

mojom_message_id_salt_suffix_path
    Current value (from the default) = ""
      From //mojo/public/tools/bindings/mojom.gni:90

msan_track_origins
    Current value (from the default) = 2
      From //build/config/sanitizers/sanitizers.gni:38

    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.

msvc_use_absolute_paths
    Current value (from the default) = false
      From //build/toolchain/toolchain.gni:32

    Use absolute file paths in the compiler diagnostics and __FILE__ macro
    if needed.

msvs_xtree_patched
    Current value (from the default) = false
      From //build/config/compiler/BUILD.gn:74

    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.

ndk_supports_nativewindow
    Current value (from the default) = false
      From //third_party/angle/gni/angle.gni:42

ndk_supports_vulkan
    Current value (from the default) = false
      From //third_party/angle/gni/angle.gni:41

optimize_for_fuzzing
    Current value (from the default) = false
      From //build/config/compiler/BUILD.gn:95

    Optimize for coverage guided fuzzing (balance between speed and number of
    branches)

optimize_webui
    Current value (from the default) = false
      From //ui/webui/webui_features.gni:9

    Optimize parts of Chrome's UI written with web technologies (HTML/CSS/JS)
    for runtime performance purposes. This does more work at compile time for
    speed benefits at runtime (so we skip in debug builds).

override_build_date
    Current value (from the default) = "N/A"
      From //base/BUILD.gn:39

    Override this value to give a specific build date.
    See //base/build_time.cc and //build/write_build_date_header.py for more
    details and the expected format.

ozone_auto_platforms
    Current value (from the default) = false
      From //ui/ozone/ozone.gni:10

    Select platforms automatically. Turn this off for manual control.

ozone_platform
    Current value (from the default) = ""
      From //ui/ozone/ozone.gni:16

    The platform that will used at runtime by default. This can be overridden
    with the command line flag --ozone-platform=<platform>.

ozone_platform_cast
    Current value (from the default) = false
      From //ui/ozone/ozone.gni:19

    Compile the 'cast' platform.

ozone_platform_gbm
    Current value (from the default) = false
      From //ui/ozone/ozone.gni:22

    Compile the 'gbm' platform.

ozone_platform_headless
    Current value (from the default) = false
      From //ui/ozone/ozone.gni:25

    Compile the 'headless' platform.

ozone_platform_wayland
    Current value (from the default) = false
      From //ui/ozone/ozone.gni:31

    Compile the 'wayland' platform.

ozone_platform_windows
    Current value (from the default) = false
      From //ui/ozone/ozone.gni:34

    Compile the 'windows' platform.

ozone_platform_x11
    Current value (from the default) = false
      From //ui/ozone/ozone.gni:28

    Compile the 'x11' platform.

package_arcore
    Current value (from the default) = false
      From //device/vr/buildflags/buildflags.gni:37

    TODO(crbug.com/837999, crbug.com/841389): We currently only support arm and
    we are limiting to canary and dev until binary size issues are resolved.
    TODO(crbug.com/845080): add android_channel == "dev" || "canary"

pdf_bundle_freetype
    Current value (from the default) = false
      From //third_party/pdfium/pdfium.gni:16

    Build PDFium either:
    1) When set to true, with a bundled FreeType, built from FreeType source
       code in //third_party/freetype and PDFium's FreeType configs in
       third_party/freetype/include.
    2) When set to false, use whatever FreeType target is defined in
       //build/config/freetype.

pdf_enable_v8
    Current value (from the default) = true
      From //third_party/pdfium/pdfium.gni:19

    Build PDFium either with or without v8 support.

pdf_enable_xfa
    Current value (from the default) = false
      From //third_party/pdfium/pdfium.gni:22

    Build PDFium either with or without XFA Forms support.

pdf_enable_xfa_bmp
    Current value (from the default) = true
      From //third_party/pdfium/pdfium.gni:25

    If XFA, also support bmp codec. Ignored if not XFA.

pdf_enable_xfa_gif
    Current value (from the default) = true
      From //third_party/pdfium/pdfium.gni:28

    If XFA, also support gif codec. Ignored if not XFA.

pdf_enable_xfa_png
    Current value (from the default) = true
      From //third_party/pdfium/pdfium.gni:31

    If XFA, also support png codec. Ignored if not XFA.

pdf_enable_xfa_tiff
    Current value (from the default) = true
      From //third_party/pdfium/pdfium.gni:34

    If XFA, also support png codec. Ignored if not XFA.

pdf_is_complete_lib
    Current value (from the default) = false
      From //third_party/pdfium/pdfium.gni:51

    Build a complete static library

pdf_is_standalone
    Current value (from the default) = false
      From //third_party/pdfium/pdfium.gni:48

    Build PDFium standalone

pdf_use_skia
    Current value (from the default) = false
      From //third_party/pdfium/pdfium.gni:38

    Build PDFium against Skia (experimental) rather than AGG. Use Skia to draw
    everything.

pdf_use_skia_paths
    Current value (from the default) = false
      From //third_party/pdfium/pdfium.gni:42

    Build PDFium against Skia (experimental) rather than AGG. Use Skia to draw
    paths.

pdf_use_win32_gdi
    Current value (from the default) = true
      From //third_party/pdfium/pdfium.gni:45

    Build PDFium with or without experimental win32 GDI APIs.

pgo_build
    Current value (from the default) = false
      From //chrome/common/features.gni:62

    Indicates if the build is using PGO.

pgo_data_path
    Current value (from the default) = ""
      From //build/config/compiler/pgo/pgo.gni:16

    When using chrome_pgo_phase = 2, read profile data from this path.

pkg_config
    Current value (from the default) = ""
      From //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
    Current value (from the default) = false
      From //build/config/features.gni:29

    Enables proprietary codecs and demuxers; e.g. H264, AAC, MP3, and MP4.
    We always build Google Chrome and Chromecast with proprietary codecs.
   
    Note: this flag is used by WebRTC which is DEPSed into Chrome. Moving it
    out of //build will require using the build_overrides directory.

remove_webcore_debug_symbols
    Current value = false
      From //out/my_x86_d/args.gn:24
    Overridden from the default = false
      From //third_party/blink/renderer/config.gni:21

    TODO: send a PSA out to tell people to switch to blink_symbol_level
    and remove this.
    If true, doesn't compile debug symbols into webcore reducing the
    size of the binary and increasing the speed of gdb.

ro_segment_workaround_for_valgrind
    Current value (from the default) = false
      From //build/config/compiler/BUILD.gn:129

    Set to true to pass --no-rosegment to lld. This is a workaround
    for a KI issue in Valgrind,
    https://bugs.kde.org/show_bug.cgi?id=384727

root_extra_deps
    Current value (from the default) = []
      From //BUILD.gn:37

    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_audio_device_plays_sinus_tone
    Current value (from the default) = false
      From //third_party/webrtc/webrtc.gni:139

    When set to true, replace the audio output with a sinus tone at 440Hz.
    The ADM will ask for audio data from WebRTC but instead of reading real
    audio samples from NetEQ, a sinus tone will be generated and replace the
    real audio samples.

rtc_build_examples
    Current value (from the default) = true
      From //third_party/webrtc/webrtc.gni:78

    Set this to false to skip building examples.

rtc_build_json
    Current value (from the default) = true
      From //third_party/webrtc/webrtc.gni:171

    Disable these to not build components which can be externally provided.

rtc_build_libevent
    Current value (from the default) = false
      From //third_party/webrtc/webrtc.gni:184

rtc_build_libsrtp
    Current value (from the default) = true
      From //third_party/webrtc/webrtc.gni:172

rtc_build_libvpx
    Current value (from the default) = true
      From //third_party/webrtc/webrtc.gni:173

rtc_build_opus
    Current value (from the default) = true
      From //third_party/webrtc/webrtc.gni:175

rtc_build_ssl
    Current value (from the default) = true
      From //third_party/webrtc/webrtc.gni:176

rtc_build_tools
    Current value (from the default) = true
      From //third_party/webrtc/webrtc.gni:81

    Set this to false to skip building tools.

rtc_build_usrsctp
    Current value (from the default) = true
      From //third_party/webrtc/webrtc.gni:177

rtc_build_with_neon
    Current value (from the default) = false
      From //third_party/webrtc/webrtc.gni:119

rtc_builtin_ssl_root_certificates
    Current value (from the default) = true
      From //third_party/webrtc/webrtc.gni:37

    Setting this to false will require the API user to pass in their own
    SSLCertificateVerifier to verify the certificates presented from a
    TLS-TURN server. In return disabling this saves around 100kb in the binary.

rtc_enable_android_aaudio
    Current value (from the default) = false
      From //third_party/webrtc/webrtc.gni:91

    Enable use of Android AAudio which requires Android SDK 26 or above and
    NDK r16 or above.

rtc_enable_android_opensl
    Current value (from the default) = false
      From //third_party/webrtc/webrtc.gni:94

    TODO(henrika): can this flag be removed?

rtc_enable_bwe_test_logging
    Current value (from the default) = false
      From //third_party/webrtc/webrtc.gni:75

    Set this to true to enable BWE test logging.

rtc_enable_external_auth
    Current value (from the default) = true
      From //third_party/webrtc/webrtc.gni:68

    Enable when an external authentication mechanism is used for performing
    packet authentication for RTP packets instead of libsrtp.

rtc_enable_intelligibility_enhancer
    Current value (from the default) = false
      From //third_party/webrtc/webrtc.gni:64

    Disable the code for the intelligibility enhancer by default.

rtc_enable_libevent
    Current value (from the default) = false
      From //third_party/webrtc/webrtc.gni:183

rtc_enable_protobuf
    Current value (from the default) = true
      From //third_party/webrtc/webrtc.gni:165

    Enables the use of protocol buffers for debug recordings.

rtc_enable_sctp
    Current value (from the default) = true
      From //third_party/webrtc/webrtc.gni:168

    Set this to disable building with support for SCTP data channels.

rtc_include_ilbc
    Current value = false
      From //.gn:65
    Overridden from the default = true
      From //third_party/webrtc/webrtc.gni:40

    Include the iLBC audio codec?

rtc_include_internal_audio_device
    Current value (from the default) = false
      From //third_party/webrtc/webrtc.gni:199

    Chromium uses its own IO handling, so the internal ADM is only built for
    standalone WebRTC.

rtc_include_opus
    Current value (from the default) = true
      From //third_party/webrtc/webrtc.gni:43

    Disable this to avoid building the Opus audio codec.

rtc_include_pulse_audio
    Current value (from the default) = false
      From //third_party/webrtc/webrtc.gni:195

    Excluded in Chromium since its prerequisites don't require Pulse Audio.

rtc_include_tests
    Current value (from the default) = false
      From //third_party/webrtc/webrtc.gni:202

    Include tests in standalone checkout.

rtc_initialize_ffmpeg
    Current value (from the default) = false
      From //third_party/webrtc/webrtc.gni:150

    FFmpeg must be initialized for |H264DecoderImpl| to work. This can be done
    by WebRTC during |H264DecoderImpl::InitDecode| or externally. FFmpeg must
    only be initialized once. Projects that initialize FFmpeg externally, such
    as Chromium, must turn this flag off so that WebRTC does not also
    initialize.

rtc_jsoncpp_root
    Current value (from the default) = "//third_party/jsoncpp/source/include"
      From //third_party/webrtc/webrtc.gni:54

    Used to specify an external Jsoncpp include path when not compiling the
    library that comes with WebRTC (i.e. rtc_build_json == 0).

rtc_libvpx_build_vp9
    Current value (from the default) = true
      From //third_party/webrtc/webrtc.gni:174

rtc_link_task_queue_impl
    Current value = false
      From //.gn:60
    Overridden from the default = true