diff --git a/build/linux/unbundle/fontconfig.gn b/build/linux/unbundle/fontconfig.gn
new file mode 100644
index 0000000..87926d5
--- /dev/null
+++ b/build/linux/unbundle/fontconfig.gn
@@ -0,0 +1,13 @@
+# Copyright 2017 The Chromium Authors
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+assert(is_linux || is_chromeos)
+
+config("fontconfig_config") {
+  libs = [ "fontconfig" ]
+}
+
+group("fontconfig") {
+  public_configs = [ ":fontconfig_config" ]
+}
diff --git a/build/linux/unbundle/freetype2.gn b/build/linux/unbundle/freetype2.gn
new file mode 100644
index 0000000..3b8cafb
--- /dev/null
+++ b/build/linux/unbundle/freetype2.gn
@@ -0,0 +1,35 @@
+# Copyright 2013 The Flutter Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//build/config/linux/pkg_config.gni")
+import("//build/shim_headers.gni")
+
+config("freetype_config") {
+  include_dirs = [ "include/freetype-flutter-config" ]
+
+  cflags = []
+
+  if (is_clang) {
+    cflags += [
+      "-Wno-unused-function",
+      "-Wno-unused-variable",
+    ]
+  }
+}
+
+pkg_config("system_freetype2") {
+  packages = [ "freetype2" ]
+}
+
+source_set("freetype2") {
+  output_name = "freetype2"
+  deps = [
+    "//third_party/libpng",
+    "//third_party/zlib",
+  ]
+  public_configs = [
+    ":freetype_config",
+    ":system_freetype2",
+  ]
+}
diff --git a/build/linux/unbundle/harfbuzz.gn b/build/linux/unbundle/harfbuzz.gn
new file mode 100644
index 0000000..72d3e06
--- /dev/null
+++ b/build/linux/unbundle/harfbuzz.gn
@@ -0,0 +1,31 @@
+# Copyright 2013 The Flutter Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//build/config/linux/pkg_config.gni")
+
+pkg_config("system_harfbuzz") {
+  packages = [ "harfbuzz" ]
+}
+
+pkg_config("system_harfbuzz_subset") {
+  packages = [ "harfbuzz-subset" ]
+}
+
+source_set("harfbuzz") {
+  output_name = "harfbuzz"
+  deps = [
+    "//third_party/freetype2",
+    "//third_party/icu:icuuc",
+  ]
+  public_configs = [ ":system_harfbuzz" ]
+}
+
+source_set("harfbuzz_subset") {
+  output_name = "harfbuzz_subset"
+  deps = [
+    "//third_party/freetype2",
+    "//third_party/icu:icuuc",
+  ]
+  public_configs = [ ":system_harfbuzz_subset" ]
+}
diff --git a/build/linux/unbundle/icu.gn b/build/linux/unbundle/icu.gn
new file mode 100644
index 0000000..9e54d4e
--- /dev/null
+++ b/build/linux/unbundle/icu.gn
@@ -0,0 +1,262 @@
+# Copyright 2016 The Chromium Authors
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//build/config/linux/pkg_config.gni")
+import("//build/shim_headers.gni")
+
+group("icu") {
+  public_deps = [
+    ":icui18n",
+    ":icuuc",
+  ]
+}
+
+config("icu_config") {
+  defines = [
+    "USING_SYSTEM_ICU=1",
+    "ICU_UTIL_DATA_IMPL=ICU_UTIL_DATA_STATIC",
+
+    # U_EXPORT (defined in unicode/platform.h) is used to set public visibility
+    # on classes through the U_COMMON_API and U_I18N_API macros (among others).
+    # When linking against the system ICU library, we want its symbols to have
+    # public LTO visibility. This disables CFI checks for the ICU classes and
+    # allows whole-program optimization to be applied to the rest of Chromium.
+    #
+    # Both U_COMMON_API and U_I18N_API macros would be defined to U_EXPORT only
+    # when U_COMBINED_IMPLEMENTATION is defined (see unicode/utypes.h). Because
+    # we override the default system UCHAR_TYPE (char16_t), it is not possible
+    # to use U_COMBINED_IMPLEMENTATION at this moment, meaning the U_COMMON_API
+    # and U_I18N_API macros are set to U_IMPORT which is an empty definition.
+    #
+    # Until building with UCHAR_TYPE=char16_t is supported, one way to apply
+    # public visibility (and thus public LTO visibility) to all ICU classes is
+    # to define U_IMPORT to have the same value as U_EXPORT. For more details,
+    # please see: https://crbug.com/822820
+    "U_IMPORT=U_EXPORT",
+  ]
+}
+
+pkg_config("system_icui18n") {
+  packages = [ "icu-i18n" ]
+}
+
+pkg_config("system_icuuc") {
+  packages = [ "icu-uc" ]
+}
+
+source_set("icui18n") {
+  public_deps = [ ":icui18n_shim" ]
+  public_configs = [
+    ":icu_config",
+    ":system_icui18n",
+  ]
+}
+
+source_set("icuuc") {
+  public_deps = [ ":icuuc_shim" ]
+  public_configs = [
+    ":icu_config",
+    ":system_icuuc",
+  ]
+}
+
+group("icui18n_hidden_visibility") {
+  public_deps = [ ":icui18n" ]
+}
+
+group("icuuc_hidden_visibility") {
+  public_deps = [ ":icuuc" ]
+}
+
+shim_headers("icui18n_shim") {
+  root_path = "source/i18n"
+  headers = [
+    # This list can easily be updated using the commands below:
+    # cd third_party/icu/source/i18n
+    # find unicode -iname '*.h' -printf '    "%p",\n' | LC_ALL=C sort -u
+    "unicode/alphaindex.h",
+    "unicode/basictz.h",
+    "unicode/calendar.h",
+    "unicode/choicfmt.h",
+    "unicode/coleitr.h",
+    "unicode/coll.h",
+    "unicode/compactdecimalformat.h",
+    "unicode/curramt.h",
+    "unicode/currpinf.h",
+    "unicode/currunit.h",
+    "unicode/datefmt.h",
+    "unicode/dcfmtsym.h",
+    "unicode/decimfmt.h",
+    "unicode/dtfmtsym.h",
+    "unicode/dtitvfmt.h",
+    "unicode/dtitvinf.h",
+    "unicode/dtptngen.h",
+    "unicode/dtrule.h",
+    "unicode/fieldpos.h",
+    "unicode/fmtable.h",
+    "unicode/format.h",
+    "unicode/fpositer.h",
+    "unicode/gender.h",
+    "unicode/gregocal.h",
+    "unicode/listformatter.h",
+    "unicode/measfmt.h",
+    "unicode/measunit.h",
+    "unicode/measure.h",
+    "unicode/msgfmt.h",
+    "unicode/numfmt.h",
+    "unicode/numsys.h",
+    "unicode/plurfmt.h",
+    "unicode/plurrule.h",
+    "unicode/rbnf.h",
+    "unicode/rbtz.h",
+    "unicode/regex.h",
+    "unicode/region.h",
+    "unicode/reldatefmt.h",
+    "unicode/scientificnumberformatter.h",
+    "unicode/search.h",
+    "unicode/selfmt.h",
+    "unicode/simpletz.h",
+    "unicode/smpdtfmt.h",
+    "unicode/sortkey.h",
+    "unicode/stsearch.h",
+    "unicode/tblcoll.h",
+    "unicode/timezone.h",
+    "unicode/tmunit.h",
+    "unicode/tmutamt.h",
+    "unicode/tmutfmt.h",
+    "unicode/translit.h",
+    "unicode/tzfmt.h",
+    "unicode/tznames.h",
+    "unicode/tzrule.h",
+    "unicode/tztrans.h",
+    "unicode/ucal.h",
+    "unicode/ucol.h",
+    "unicode/ucoleitr.h",
+    "unicode/ucsdet.h",
+    "unicode/udat.h",
+    "unicode/udateintervalformat.h",
+    "unicode/udatpg.h",
+    "unicode/ufieldpositer.h",
+    "unicode/uformattable.h",
+    "unicode/ugender.h",
+    "unicode/ulocdata.h",
+    "unicode/umsg.h",
+    "unicode/unirepl.h",
+    "unicode/unum.h",
+    "unicode/unumsys.h",
+    "unicode/upluralrules.h",
+    "unicode/uregex.h",
+    "unicode/uregion.h",
+    "unicode/ureldatefmt.h",
+    "unicode/usearch.h",
+    "unicode/uspoof.h",
+    "unicode/utmscale.h",
+    "unicode/utrans.h",
+    "unicode/vtzone.h",
+  ]
+}
+
+shim_headers("icuuc_shim") {
+  root_path = "source/common"
+  headers = [
+    # This list can easily be updated using the commands below:
+    # cd third_party/icu/source/common
+    # find unicode -iname '*.h' -printf '    "%p",\n' | LC_ALL=C sort -u
+    "unicode/appendable.h",
+    "unicode/brkiter.h",
+    "unicode/bytestream.h",
+    "unicode/bytestrie.h",
+    "unicode/bytestriebuilder.h",
+    "unicode/caniter.h",
+    "unicode/casemap.h",
+    "unicode/char16ptr.h",
+    "unicode/chariter.h",
+    "unicode/dbbi.h",
+    "unicode/docmain.h",
+    "unicode/dtintrv.h",
+    "unicode/edits.h",
+    "unicode/enumset.h",
+    "unicode/errorcode.h",
+    "unicode/filteredbrk.h",
+    "unicode/icudataver.h",
+    "unicode/icuplug.h",
+    "unicode/idna.h",
+    "unicode/localematcher.h",
+    "unicode/localpointer.h",
+    "unicode/locdspnm.h",
+    "unicode/locid.h",
+    "unicode/messagepattern.h",
+    "unicode/normalizer2.h",
+    "unicode/normlzr.h",
+    "unicode/parseerr.h",
+    "unicode/parsepos.h",
+    "unicode/platform.h",
+    "unicode/ptypes.h",
+    "unicode/putil.h",
+    "unicode/rbbi.h",
+    "unicode/rep.h",
+    "unicode/resbund.h",
+    "unicode/schriter.h",
+    "unicode/simpleformatter.h",
+    "unicode/std_string.h",
+    "unicode/strenum.h",
+    "unicode/stringpiece.h",
+    "unicode/stringtriebuilder.h",
+    "unicode/symtable.h",
+    "unicode/ubidi.h",
+    "unicode/ubiditransform.h",
+    "unicode/ubrk.h",
+    "unicode/ucasemap.h",
+    "unicode/ucat.h",
+    "unicode/uchar.h",
+    "unicode/ucharstrie.h",
+    "unicode/ucharstriebuilder.h",
+    "unicode/uchriter.h",
+    "unicode/uclean.h",
+    "unicode/ucnv.h",
+    "unicode/ucnv_cb.h",
+    "unicode/ucnv_err.h",
+    "unicode/ucnvsel.h",
+    "unicode/uconfig.h",
+    "unicode/ucurr.h",
+    "unicode/udata.h",
+    "unicode/udisplaycontext.h",
+    "unicode/uenum.h",
+    "unicode/uidna.h",
+    "unicode/uiter.h",
+    "unicode/uldnames.h",
+    "unicode/ulistformatter.h",
+    "unicode/uloc.h",
+    "unicode/umachine.h",
+    "unicode/umisc.h",
+    "unicode/unifilt.h",
+    "unicode/unifunct.h",
+    "unicode/unimatch.h",
+    "unicode/uniset.h",
+    "unicode/unistr.h",
+    "unicode/unorm.h",
+    "unicode/unorm2.h",
+    "unicode/uobject.h",
+    "unicode/urename.h",
+    "unicode/urep.h",
+    "unicode/ures.h",
+    "unicode/uscript.h",
+    "unicode/uset.h",
+    "unicode/usetiter.h",
+    "unicode/ushape.h",
+    "unicode/usprep.h",
+    "unicode/ustring.h",
+    "unicode/ustringtrie.h",
+    "unicode/utext.h",
+    "unicode/utf.h",
+    "unicode/utf16.h",
+    "unicode/utf32.h",
+    "unicode/utf8.h",
+    "unicode/utf_old.h",
+    "unicode/utrace.h",
+    "unicode/utypes.h",
+    "unicode/uvernum.h",
+    "unicode/uversion.h",
+  ]
+}
diff --git a/build/linux/unbundle/libjpeg-turbo.gn b/build/linux/unbundle/libjpeg-turbo.gn
new file mode 100644
index 0000000..be0c674
--- /dev/null
+++ b/build/linux/unbundle/libjpeg-turbo.gn
@@ -0,0 +1,11 @@
+# Copyright 2013 The Flutter Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+config("libjpeg_config") {
+  libs = [ "jpeg" ]
+}
+
+group("libjpeg") {
+  public_configs = [ ":libjpeg_config" ]
+}
diff --git a/build/linux/unbundle/libpng.gn b/build/linux/unbundle/libpng.gn
new file mode 100644
index 0000000..91e0ee4
--- /dev/null
+++ b/build/linux/unbundle/libpng.gn
@@ -0,0 +1,23 @@
+# Copyright 2016 The Chromium Authors
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//build/config/linux/pkg_config.gni")
+import("//build/shim_headers.gni")
+
+pkg_config("libpng_config") {
+  packages = [ "libpng" ]
+}
+
+shim_headers("libpng_shim") {
+  root_path = "."
+  headers = [
+    "png.h",
+    "pngconf.h",
+  ]
+}
+
+source_set("libpng") {
+  deps = [ ":libpng_shim" ]
+  public_configs = [ ":libpng_config" ]
+}
diff --git a/build/linux/unbundle/libwebp.gn b/build/linux/unbundle/libwebp.gn
new file mode 100644
index 0000000..708cc9c
--- /dev/null
+++ b/build/linux/unbundle/libwebp.gn
@@ -0,0 +1,35 @@
+# Copyright 2016 The Chromium Authors
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//build/config/linux/pkg_config.gni")
+import("//build/shim_headers.gni")
+
+pkg_config("system_libwebp") {
+  packages = [
+    "libwebp",
+    "libwebpdemux",
+    "libwebpmux",
+  ]
+}
+
+shim_headers("libwebp_shim") {
+  root_path = "src/src"
+  headers = [
+    "webp/decode.h",
+    "webp/demux.h",
+    "webp/encode.h",
+    "webp/mux.h",
+    "webp/mux_types.h",
+    "webp/types.h",
+  ]
+}
+
+source_set("libwebp_webp") {
+  deps = [ ":libwebp_shim" ]
+  public_configs = [ ":system_libwebp" ]
+}
+
+group("libwebp") {
+  deps = [ ":libwebp_webp" ]
+}
diff --git a/build/linux/unbundle/libxml.gn b/build/linux/unbundle/libxml.gn
new file mode 100644
index 0000000..b42d044
--- /dev/null
+++ b/build/linux/unbundle/libxml.gn
@@ -0,0 +1,13 @@
+# Copyright 2016 The Chromium Authors
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//build/config/linux/pkg_config.gni")
+
+pkg_config("system_libxml") {
+  packages = [ "libxml-2.0" ]
+}
+
+source_set("libxml") {
+  public_configs = [ ":system_libxml" ]
+}
diff --git a/build/linux/unbundle/replace_gn_files.py b/build/linux/unbundle/replace_gn_files.py
new file mode 100755
index 0000000..b8b24c6
--- /dev/null
+++ b/build/linux/unbundle/replace_gn_files.py
@@ -0,0 +1,101 @@
+#!/usr/bin/env python3
+# Copyright 2016 The Chromium Authors
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""
+Replaces GN files in tree with files from here that
+make the build use system libraries.
+"""
+
+import argparse
+import os
+import shutil
+import sys
+
+
+REPLACEMENTS = {
+  # Use system libabsl_2xxx. These 18 shims MUST be used together.
+  'absl_algorithm': 'third_party/abseil-cpp/absl/algorithm/BUILD.gn',
+  'absl_base': 'third_party/abseil-cpp/absl/base/BUILD.gn',
+  'absl_cleanup': 'third_party/abseil-cpp/absl/cleanup/BUILD.gn',
+  'absl_container': 'third_party/abseil-cpp/absl/container/BUILD.gn',
+  'absl_debugging': 'third_party/abseil-cpp/absl/debugging/BUILD.gn',
+  'absl_flags': 'third_party/abseil-cpp/absl/flags/BUILD.gn',
+  'absl_functional': 'third_party/abseil-cpp/absl/functional/BUILD.gn',
+  'absl_hash': 'third_party/abseil-cpp/absl/hash/BUILD.gn',
+  'absl_memory': 'third_party/abseil-cpp/absl/memory/BUILD.gn',
+  'absl_meta': 'third_party/abseil-cpp/absl/meta/BUILD.gn',
+  'absl_numeric': 'third_party/abseil-cpp/absl/numeric/BUILD.gn',
+  'absl_random': 'third_party/abseil-cpp/absl/random/BUILD.gn',
+  'absl_status': 'third_party/abseil-cpp/absl/status/BUILD.gn',
+  'absl_strings': 'third_party/abseil-cpp/absl/strings/BUILD.gn',
+  'absl_synchronization': 'third_party/abseil-cpp/absl/synchronization/BUILD.gn',
+  'absl_time': 'third_party/abseil-cpp/absl/time/BUILD.gn',
+  'absl_types': 'third_party/abseil-cpp/absl/types/BUILD.gn',
+  'absl_utility': 'third_party/abseil-cpp/absl/utility/BUILD.gn',
+  #
+  'fontconfig': 'third_party/fontconfig/BUILD.gn',
+  'freetype2': 'third_party/freetype2/BUILD.gn',
+  'harfbuzz': 'third_party/harfbuzz/BUILD.gn',
+  'icu': 'third_party/icu/BUILD.gn',
+  'libjpeg-turbo': 'third_party/libjpeg-turbo/BUILD.gn',
+  'libpng': 'third_party/libpng/BUILD.gn',
+  'libwebp': 'build/secondary/third_party/libwebp/BUILD.gn',
+  'libxml': 'third_party/libxml/BUILD.gn',
+  'libXNVCtrl': 'third_party/angle/src/third_party/libXNVCtrl/BUILD.gn',
+  'sqlite': 'third_party/sqlite/BUILD.gn',
+  # Use system libSPIRV-Tools in Swiftshader. These two shims MUST be used together.
+  'swiftshader-SPIRV-Headers': 'third_party/swiftshader/third_party/SPIRV-Headers/BUILD.gn',
+  'swiftshader-SPIRV-Tools': 'third_party/swiftshader/third_party/SPIRV-Tools/BUILD.gn',
+  # Use system libSPIRV-Tools inside ANGLE. These two shims MUST be used together
+  # and can only be used if WebGPU is not compiled (use_dawn=false)
+  'vulkan-SPIRV-Headers': 'third_party/vulkan-deps/spirv-headers/src/BUILD.gn',
+  'vulkan-SPIRV-Tools': 'third_party/vulkan-deps/spirv-tools/src/BUILD.gn',
+  #
+  'zlib': 'third_party/zlib/BUILD.gn',
+}
+
+
+def DoMain(argv):
+  my_dirname = os.path.dirname(__file__)
+  source_tree_root = os.path.abspath(
+    os.path.join(my_dirname, '..', '..', '..'))
+
+  parser = argparse.ArgumentParser()
+  parser.add_argument('--system-libraries', nargs='*', default=[])
+  parser.add_argument('--undo', action='store_true')
+
+  args = parser.parse_args(argv)
+
+  handled_libraries = set()
+  for lib, path in REPLACEMENTS.items():
+    if lib not in args.system_libraries:
+      continue
+    handled_libraries.add(lib)
+
+    if args.undo:
+      # Restore original file, and also remove the backup.
+      # This is meant to restore the source tree to its original state.
+      os.rename(os.path.join(source_tree_root, path + '.orig'),
+                os.path.join(source_tree_root, path))
+    else:
+      # Create a backup copy for --undo.
+      shutil.copyfile(os.path.join(source_tree_root, path),
+                      os.path.join(source_tree_root, path + '.orig'))
+
+      # Copy the GN file from directory of this script to target path.
+      shutil.copyfile(os.path.join(my_dirname, '%s.gn' % lib),
+                      os.path.join(source_tree_root, path))
+
+  unhandled_libraries = set(args.system_libraries) - handled_libraries
+  if unhandled_libraries:
+    print('Unrecognized system libraries requested: %s' % ', '.join(
+        sorted(unhandled_libraries)), file=sys.stderr)
+    return 1
+
+  return 0
+
+
+if __name__ == '__main__':
+  sys.exit(DoMain(sys.argv[1:]))
diff --git a/build/linux/unbundle/sqlite.gn b/build/linux/unbundle/sqlite.gn
new file mode 100644
index 0000000..e6c653d
--- /dev/null
+++ b/build/linux/unbundle/sqlite.gn
@@ -0,0 +1,20 @@
+# Copyright 2013 The Flutter Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//build/config/linux/pkg_config.gni")
+import("//build/shim_headers.gni")
+
+pkg_config("system_sqlite") {
+  packages = [ "sqlite3" ]
+}
+
+shim_headers("sqlite_shim") {
+  root_path = "."
+  headers = [ "sqlite3.h" ]
+}
+
+source_set("sqlite") {
+  public_deps = [ ":sqlite_shim" ]
+  public_configs = [ ":system_sqlite" ]
+}
diff --git a/build/linux/unbundle/zlib.gn b/build/linux/unbundle/zlib.gn
new file mode 100644
index 0000000..6daf3c6
--- /dev/null
+++ b/build/linux/unbundle/zlib.gn
@@ -0,0 +1,72 @@
+# Copyright 2016 The Chromium Authors
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//build/shim_headers.gni")
+
+declare_args() {
+  use_zlib_ng = false
+}
+
+if (use_zlib_ng) {
+  _suffix = "-ng"
+} else {
+  _suffix = ""
+}
+
+shim_headers("zlib_shim") {
+  root_path = "."
+  headers = [ "zlib.h%zlib$_suffix.h" ]
+  additional_includes = [ "third_party" ]
+}
+
+config("system_zlib") {
+  defines = [ "USE_SYSTEM_ZLIB=1" ]
+}
+
+config("zlib_config") {
+  configs = [ ":system_zlib" ]
+}
+
+source_set("zlib") {
+  public_deps = [ ":zlib_shim" ]
+  libs = [ "z$_suffix" ]
+  public_configs = [ ":system_zlib" ]
+}
+
+shim_headers("minizip_shim") {
+  root_path = "contrib"
+  headers = [
+    "minizip/crypt.h",
+    "minizip/ioapi.h",
+    "minizip/iowin32.h",
+    "minizip/mztools.h",
+    "minizip/unzip.h",
+    "minizip/zip.h",
+  ]
+}
+
+source_set("minizip") {
+  deps = [ ":minizip_shim" ]
+  libs = [ "minizip" ]
+}
+
+static_library("zip") {
+  sources = [
+    "google/zip.cc",
+    "google/zip.h",
+    "google/zip_internal.cc",
+    "google/zip_internal.h",
+    "google/zip_reader.cc",
+    "google/zip_reader.h",
+  ]
+  deps = [ ":minizip" ]
+}
+
+static_library("compression_utils") {
+  sources = [
+    "google/compression_utils.cc",
+    "google/compression_utils.h",
+  ]
+  deps = [ ":zlib" ]
+}
diff --git a/build/shim_headers.gni b/build/shim_headers.gni
new file mode 100644
index 0000000..1d24e0a
--- /dev/null
+++ b/build/shim_headers.gni
@@ -0,0 +1,42 @@
+# Copyright 2016 The Chromium Authors
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+template("shim_headers") {
+  action_name = "gen_${target_name}"
+  config_name = "${target_name}_config"
+  shim_headers_path = "${root_gen_dir}/shim_headers/${target_name}"
+  config(config_name) {
+    include_dirs = [ shim_headers_path ]
+    if (defined(invoker.additional_includes)) {
+      foreach(i, invoker.additional_includes) {
+        include_dirs += [ shim_headers_path + "/" + i ]
+      }
+    }
+  }
+  action(action_name) {
+    script = "//tools/generate_shim_headers.py"
+    args = [
+      "--generate",
+      "--headers-root",
+      rebase_path(invoker.root_path),
+      "--output-directory",
+      rebase_path(shim_headers_path),
+    ]
+    if (defined(invoker.prefix)) {
+      args += [
+        "--prefix",
+        invoker.prefix,
+      ]
+    }
+    args += invoker.headers
+    outputs = []
+    foreach(h, invoker.headers) {
+      outputs += [ shim_headers_path + "/" +
+                   rebase_path(invoker.root_path, "//") + "/" + h ]
+    }
+  }
+  group(target_name) {
+    public_deps = [ ":${action_name}" ]
+    all_dependent_configs = [ ":${config_name}" ]
+  }
+}
diff --git a/tools/generate_shim_headers.py b/tools/generate_shim_headers.py
new file mode 100644
index 0000000..aaa16f8
--- /dev/null
+++ b/tools/generate_shim_headers.py
@@ -0,0 +1,116 @@
+#!/usr/bin/env python
+# Copyright 2012 The Chromium Authors
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""
+Generates shim headers that mirror the directory structure of bundled headers,
+but just forward to the system ones.
+
+This allows seamless compilation against system headers with no changes
+to our source code.
+"""
+
+
+import optparse
+import os.path
+import sys
+
+
+SHIM_TEMPLATE = """
+#if defined(OFFICIAL_BUILD)
+#error shim headers must not be used in official builds!
+#endif
+"""
+
+
+def GeneratorMain(argv):
+  parser = optparse.OptionParser()
+  parser.add_option('--headers-root', action='append')
+  parser.add_option('--define', action='append')
+  parser.add_option('--output-directory')
+  parser.add_option('--prefix', default='')
+  parser.add_option('--use-include-next', action='store_true')
+  parser.add_option('--outputs', action='store_true')
+  parser.add_option('--generate', action='store_true')
+
+  options, args = parser.parse_args(argv)
+
+  if not options.headers_root:
+    parser.error('Missing --headers-root parameter.')
+  if not options.output_directory:
+    parser.error('Missing --output-directory parameter.')
+  if not args:
+    parser.error('Missing arguments - header file names.')
+
+  source_tree_root = os.path.abspath(
+    os.path.join(os.path.dirname(__file__), '..'))
+
+  for root in options.headers_root:
+    target_directory = os.path.join(
+      options.output_directory,
+      os.path.relpath(root, source_tree_root))
+    if options.generate and not os.path.exists(target_directory):
+      os.makedirs(target_directory)
+
+    for header_spec in args:
+      if ';' in header_spec:
+        (header_filename,
+         include_before,
+         include_after) = header_spec.split(';', 2)
+      else:
+        header_filename = header_spec
+        include_before = ''
+        include_after = ''
+      if '%' in header_filename:
+        (header_filename,
+         upstream_header_filename) = header_filename.split('%', 1)
+      else:
+        upstream_header_filename = header_filename
+      if options.outputs:
+        yield os.path.join(target_directory, header_filename)
+      if options.generate:
+        header_path = os.path.join(target_directory, header_filename)
+        header_dir = os.path.dirname(header_path)
+        if not os.path.exists(header_dir):
+          os.makedirs(header_dir)
+        with open(header_path, 'w') as f:
+          f.write(SHIM_TEMPLATE)
+
+          if options.define:
+            for define in options.define:
+              key, value = define.split('=', 1)
+              # This non-standard push_macro extension is supported
+              # by compilers we support (GCC, clang).
+              f.write('#pragma push_macro("%s")\n' % key)
+              f.write('#undef %s\n' % key)
+              f.write('#define %s %s\n' % (key, value))
+
+          if include_before:
+            for header in include_before.split(':'):
+              f.write('#include %s\n' % header)
+
+          include_target = options.prefix + upstream_header_filename
+          if options.use_include_next:
+            f.write('#include_next <%s>\n' % include_target)
+          else:
+            f.write('#include <%s>\n' % include_target)
+
+          if include_after:
+            for header in include_after.split(':'):
+              f.write('#include %s\n' % header)
+
+          if options.define:
+            for define in options.define:
+              key, value = define.split('=', 1)
+              # This non-standard pop_macro extension is supported
+              # by compilers we support (GCC, clang).
+              f.write('#pragma pop_macro("%s")\n' % key)
+
+
+def DoMain(argv):
+  return '\n'.join(GeneratorMain(argv))
+
+
+if __name__ == '__main__':
+  DoMain(sys.argv[1:])
--- /dev/null
+++ ./build/linux/unbundle/vulkan-SPIRV-Headers.gn
@@ -0,0 +1,19 @@
+# This shim can only be used if you build Chromium without DAWN
+
+import("//build/shim_headers.gni")
+
+shim_headers("vulkan-SPIRV-Headers_shim") {
+  root_path = "include"
+  headers = [
+    "spirv/unified1/GLSL.std.450.h",
+    "spirv/unified1/NonSemanticClspvReflection.h",
+    "spirv/unified1/NonSemanticDebugPrintf.h",
+    "spirv/unified1/OpenCL.std.h",
+    "spirv/unified1/spirv.h",
+    "spirv/unified1/spirv.hpp",
+  ]
+}
+
+source_set("spv_headers") {
+  deps = [ ":vulkan-SPIRV-Headers_shim" ]
+}
--- /dev/null
+++ ./build/linux/unbundle/vulkan-SPIRV-Tools.gn
@@ -0,0 +1,73 @@
+# This shim can only be used if you build Chromium without DAWN
+
+import("//build/config/linux/pkg_config.gni")
+import("//build/shim_headers.gni")
+
+pkg_config("spvtools_internal_config") {
+  packages = [ "SPIRV-Tools" ]
+}
+
+shim_headers("vulkan-SPIRV-Tools_shim") {
+  root_path = "include"
+  headers = [
+    "spirv-tools/instrument.hpp",
+    "spirv-tools/libspirv.h",
+    "spirv-tools/libspirv.hpp",
+    "spirv-tools/linker.hpp",
+    "spirv-tools/optimizer.hpp",
+  ]
+}
+
+source_set("SPIRV-Tools") {
+  deps = [ ":vulkan-SPIRV-Tools_shim" ]
+  public_configs = [ ":spvtools_internal_config" ]
+}
+
+source_set("spvtools") {
+  deps = [ ":vulkan-SPIRV-Tools_shim" ]
+  public_configs = [ ":spvtools_internal_config" ]
+}
+
+source_set("spvtools_core_enums_unified1") {
+  deps = [ ":vulkan-SPIRV-Tools_shim" ]
+  public_configs = [ ":spvtools_internal_config" ]
+}
+
+source_set("spvtools_core_tables_unified1") {
+  deps = [ ":vulkan-SPIRV-Tools_shim" ]
+  public_configs = [ ":spvtools_internal_config" ]
+}
+
+source_set("spvtools_headers") {
+  deps = [ ":vulkan-SPIRV-Tools_shim" ]
+  public_configs = [ ":spvtools_internal_config" ]
+}
+
+source_set("spvtools_language_header_cldebuginfo100") {
+  deps = [ ":vulkan-SPIRV-Tools_shim" ]
+  public_configs = [ ":spvtools_internal_config" ]
+}
+
+source_set("spvtools_language_header_debuginfo") {
+  deps = [ ":vulkan-SPIRV-Tools_shim" ]
+  public_configs = [ ":spvtools_internal_config" ]
+}
+
+source_set("spvtools_language_header_vkdebuginfo100") {
+  deps = [ ":vulkan-SPIRV-Tools_shim" ]
+  public_configs = [ ":spvtools_internal_config" ]
+}
+
+source_set("spvtools_opt") {
+  deps = [ ":vulkan-SPIRV-Tools_shim" ]
+  public_configs = [ ":spvtools_internal_config" ]
+}
+
+config("spvtools_public_config") {
+  configs = [ ":spvtools_internal_config" ]
+}
+
+source_set("spvtools_val") {
+  deps = [ ":vulkan-SPIRV-Tools_shim" ]
+  public_configs = [ ":spvtools_internal_config" ]
+}