diff --git a/CHROMIUM_VERSION b/CHROMIUM_VERSION
new file mode 100644
index 0000000000..639d5b2b28
--- /dev/null
+++ b/CHROMIUM_VERSION
@@ -0,0 +1 @@
+100.0.4896.60
diff --git a/tools/build_test.sh b/tools/build_test.sh
new file mode 100755
index 0000000000..24be765cae
--- /dev/null
+++ b/tools/build_test.sh
@@ -0,0 +1,101 @@
+#!/bin/sh
+set -ex
+cd src
+
+unset EXTRA_FLAGS
+unset OPENWRT_FLAGS
+ccache -C
+
+./get-clang.sh
+
+for i in x64 x86 arm64 arm mipsel mips64el; do
+  unset EXTRA_FLAGS
+  unset OPENWRT_FLAGS
+  export EXTRA_FLAGS="target_cpu=\"$i\""
+  ./get-clang.sh
+done
+
+for i in x64 x86 arm64 arm; do
+  unset EXTRA_FLAGS
+  unset OPENWRT_FLAGS
+  export EXTRA_FLAGS="target_cpu=\"$i\" target_os=\"android\""
+  ./get-clang.sh
+done
+
+config_openwrt() {
+  arch="$1"
+  openwrt="$2"
+  target_cpu="$3"
+  extra="$4"
+  export EXTRA_FLAGS="target_cpu=\"$target_cpu\" target_os=\"openwrt\" use_allocator=\"none\" use_allocator_shim=false $extra"
+  export OPENWRT_FLAGS="arch=$arch release=19.07.7 gcc_ver=7.5.0 $openwrt"
+  ./get-clang.sh
+}
+
+config_openwrt x86_64 'target=x86 subtarget=64' x64
+config_openwrt x86 'target=x86 subtarget=generic' x86
+config_openwrt aarch64_cortex-a53 'target=sunxi subtarget=cortexa53' arm64 'arm_version=0 arm_cpu="cortex-a53"'
+config_openwrt aarch64_cortex-a72 'target=mvebu subtarget=cortexa72' arm64 'arm_version=0 arm_cpu="cortex-a72"'
+config_openwrt aarch64_generic 'target=armvirt subtarget=64' arm64
+config_openwrt arm_cortex-a5_vfpv4 'target=at91 subtarget=sama5' arm 'arm_version=0 arm_cpu="cortex-a5" arm_fpu="vfpv4" arm_float_abi="hard" arm_use_neon=false'
+config_openwrt arm_cortex-a7_neon-vfpv4 'target=sunxi subtarget=cortexa7' arm 'arm_version=0 arm_cpu="cortex-a7" arm_fpu="neon-vfpv4" arm_float_abi="hard" arm_use_neon=true'
+config_openwrt arm_cortex-a8_neon 'target=samsung subtarget=s5pv210' arm 'arm_version=0 arm_cpu="cortex-a8" arm_fpu="neon" arm_float_abi="hard" arm_use_neon=true'
+config_openwrt arm_cortex-a8_vfpv3 'target=sunxi subtarget=cortexa8' arm 'arm_version=0 arm_cpu="cortex-a8" arm_fpu="vfpv3" arm_float_abi="hard" arm_use_neon=false'
+config_openwrt arm_cortex-a9 'target=bcm53xx' arm 'arm_version=0 arm_cpu="cortex-a9" arm_float_abi="soft" arm_use_neon=false'
+config_openwrt arm_cortex-a9_neon 'target=imx6' arm 'arm_version=0 arm_cpu="cortex-a9" arm_fpu="neon" arm_float_abi="hard" arm_use_neon=true'
+config_openwrt arm_cortex-a9_vfpv3-d16 'target=tegra' arm 'arm_version=0 arm_cpu="cortex-a9" arm_fpu="vfpv3-d16" arm_float_abi="hard" arm_use_neon=false'
+config_openwrt arm_cortex-a15_neon-vfpv4 'target=armvirt subtarget=32' arm 'arm_version=0 arm_cpu="cortex-a15" arm_fpu="neon-vfpv4" arm_float_abi="hard" arm_use_neon=true'
+config_openwrt mipsel_24kc 'target=ramips subtarget=rt305x' mipsel 'mips_arch_variant="r2" mips_float_abi="soft" mips_tune="24kc" use_lld=false use_gold=false'
+config_openwrt mipsel_74kc 'target=ramips subtarget=rt3883' mipsel 'mips_arch_variant="r2" mips_float_abi="soft" mips_tune="74kc" use_lld=false use_gold=false'
+config_openwrt mipsel_mips32 'target=rb532' mipsel 'mips_arch_variant="r1" mips_float_abi="soft" use_lld=false use_gold=false'
+
+rm -f /tmp/trace
+inotifywait -m -r -o/tmp/trace --format '%w%f %e' . &
+pid=$!
+
+unset EXTRA_FLAGS
+unset OPENWRT_FLAGS
+./build.sh
+
+for i in x64 x86 arm64 arm mipsel mips64el; do
+  unset EXTRA_FLAGS
+  unset OPENWRT_FLAGS
+  export EXTRA_FLAGS="target_cpu=\"$i\""
+  ./build.sh
+done
+
+for i in x64 x86 arm64 arm; do
+  unset EXTRA_FLAGS
+  unset OPENWRT_FLAGS
+  export EXTRA_FLAGS="target_cpu=\"$i\" target_os=\"android\""
+  ./build.sh
+done
+
+build_openwrt() {
+  arch="$1"
+  openwrt="$2"
+  target_cpu="$3"
+  extra="$4"
+  export EXTRA_FLAGS="target_cpu=\"$target_cpu\" target_os=\"openwrt\" use_allocator=\"none\" use_allocator_shim=false $extra"
+  export OPENWRT_FLAGS="arch=$arch release=19.07.7 gcc_ver=7.5.0 $openwrt"
+  ./build.sh
+}
+
+build_openwrt x86_64 'target=x86 subtarget=64' x64
+build_openwrt x86 'target=x86 subtarget=generic' x86
+build_openwrt aarch64_cortex-a53 'target=sunxi subtarget=cortexa53' arm64 'arm_version=0 arm_cpu="cortex-a53"'
+build_openwrt aarch64_cortex-a72 'target=mvebu subtarget=cortexa72' arm64 'arm_version=0 arm_cpu="cortex-a72"'
+build_openwrt aarch64_generic 'target=armvirt subtarget=64' arm64
+build_openwrt arm_cortex-a5_vfpv4 'target=at91 subtarget=sama5' arm 'arm_version=0 arm_cpu="cortex-a5" arm_fpu="vfpv4" arm_float_abi="hard" arm_use_neon=false'
+build_openwrt arm_cortex-a7_neon-vfpv4 'target=sunxi subtarget=cortexa7' arm 'arm_version=0 arm_cpu="cortex-a7" arm_fpu="neon-vfpv4" arm_float_abi="hard" arm_use_neon=true'
+build_openwrt arm_cortex-a8_neon 'target=samsung subtarget=s5pv210' arm 'arm_version=0 arm_cpu="cortex-a8" arm_fpu="neon" arm_float_abi="hard" arm_use_neon=true'
+build_openwrt arm_cortex-a8_vfpv3 'target=sunxi subtarget=cortexa8' arm 'arm_version=0 arm_cpu="cortex-a8" arm_fpu="vfpv3" arm_float_abi="hard" arm_use_neon=false'
+build_openwrt arm_cortex-a9 'target=bcm53xx' arm 'arm_version=0 arm_cpu="cortex-a9" arm_float_abi="soft" arm_use_neon=false'
+build_openwrt arm_cortex-a9_neon 'target=imx6' arm 'arm_version=0 arm_cpu="cortex-a9" arm_fpu="neon" arm_float_abi="hard" arm_use_neon=true'
+build_openwrt arm_cortex-a9_vfpv3-d16 'target=tegra' arm 'arm_version=0 arm_cpu="cortex-a9" arm_fpu="vfpv3-d16" arm_float_abi="hard" arm_use_neon=false'
+build_openwrt arm_cortex-a15_neon-vfpv4 'target=armvirt subtarget=32' arm 'arm_version=0 arm_cpu="cortex-a15" arm_fpu="neon-vfpv4" arm_float_abi="hard" arm_use_neon=true'
+build_openwrt mipsel_24kc 'target=ramips subtarget=rt305x' mipsel 'mips_arch_variant="r2" mips_float_abi="soft" mips_tune="24kc" use_lld=false use_gold=false'
+build_openwrt mipsel_74kc 'target=ramips subtarget=rt3883' mipsel 'mips_arch_variant="r2" mips_float_abi="soft" mips_tune="74kc" use_lld=false use_gold=false'
+build_openwrt mipsel_mips32 'target=rb532' mipsel 'mips_arch_variant="r1" mips_float_abi="soft" use_lld=false use_gold=false'
+
+kill $pid
diff --git a/tools/build_test_stats.sh b/tools/build_test_stats.sh
new file mode 100755
index 0000000000..78199db48a
--- /dev/null
+++ b/tools/build_test_stats.sh
@@ -0,0 +1,5 @@
+#!/bin/sh
+for i in /tmp/trace.*; do
+  cut -d' ' -f1 $i | LC_ALL=C sort -u | sed 's/\/$//' | LC_ALL=C sort -u >$i.sorted
+done
+cat /tmp/trace.*.sorted | LC_ALL=C sort -u >/tmp/detected-files
diff --git a/tools/exclude.txt b/tools/exclude.txt
new file mode 100644
index 0000000000..fb8bc408f3
--- /dev/null
+++ b/tools/exclude.txt
@@ -0,0 +1,21 @@
+.gitignore
+*_unittest.cc
+*_unittest.mm
+*_unittest.nc
+*_perftest.cc
+*_test.cc
+*fuzz*
+*src/org/chromium*
+*.golden
+*.javap*
+*.pyc
+net/data/[!s]*
+net/data/s[!s]*
+net/data/ssl/[!ce]*
+net/data/ssl/c[!h]*
+net/http/transport_security_state_static.json
+net/third_party/nist-pkits
+third_party/boringssl/src/crypto/hpke/test-vectors.json
+third_party/boringssl/src/crypto/cipher_extra/test
+third_party/boringssl/src/third_party/googletest
+third_party/boringssl/src/third_party/wycheproof_testvectors
diff --git a/tools/import-upstream.sh b/tools/import-upstream.sh
new file mode 100755
index 0000000000..b3c1963c04
--- /dev/null
+++ b/tools/import-upstream.sh
@@ -0,0 +1,27 @@
+#!/bin/sh
+set -ex
+have_version=$(cut -d= -f2 src/chrome/VERSION | tr '\n' . | cut -d. -f1-4)
+want_version=$(cat CHROMIUM_VERSION)
+if [ "$have_version" = "$want_version" ]; then
+  exit 0
+fi
+name="chromium-$want_version"
+tarball="$name.tar.xz"
+url="https://commondatastorage.googleapis.com/chromium-browser-official/$tarball"
+root=$(git rev-list --max-parents=0 HEAD)
+git config core.autocrlf false
+git config core.safecrlf false
+git -c advice.detachedHead=false checkout $root
+rm -rf src
+git checkout master -- tools
+sed -i "s/^\^/$name\//" tools/include.txt
+if [ -f "/tmp/$tarball" ]; then
+  cat "/tmp/$tarball" | tar xJf - --wildcards --wildcards-match-slash -T tools/include.txt -X tools/exclude.txt
+else
+  curl "$url" -o- | tar xJf - --wildcards --wildcards-match-slash -T tools/include.txt -X tools/exclude.txt
+fi
+mv "$name" src
+git rm --quiet --force -r tools
+git add src
+git commit --quiet --amend -m "Import $name" --date=now
+git rebase --onto HEAD "$root" master
diff --git a/tools/include.txt b/tools/include.txt
new file mode 100644
index 0000000000..e5b7793105
--- /dev/null
+++ b/tools/include.txt
@@ -0,0 +1,64 @@
+^.clang-format
+^.gitattributes
+^.gitignore
+^.gn
+^AUTHORS
+^BUILD.gn
+^DEPS
+^LICENSE
+^base
+^build
+^build_overrides/build.gni
+^buildtools/deps_revisions.gni
+^buildtools/third_party/eu-strip/bin/eu-strip
+^buildtools/third_party/libc++/BUILD.gn
+^buildtools/third_party/libc++/__config_site
+^buildtools/third_party/libc++/trunk/include
+^buildtools/third_party/libc++/trunk/src
+^buildtools/third_party/libc++abi/BUILD.gn
+^buildtools/third_party/libc++abi/cxa_demangle_stub.cc
+^buildtools/third_party/libc++abi/trunk/include
+^buildtools/third_party/libc++abi/trunk/src
+^buildtools/third_party/libunwind
+^chrome/VERSION
+^chrome/android/profiles/newest.txt
+^chrome/app/theme/chromium/BRANDING
+^chrome/build/*.txt
+^components/version_info
+^crypto
+^ipc/ipc_param_traits.h
+^net
+^testing/gtest/include/gtest/gtest_prod.h
+^third_party/abseil-cpp
+^third_party/angle/dotfile_settings.gni
+^third_party/angle/src/commit_id.py
+^third_party/angle/scripts/file_exists.py
+^third_party/apple_apsl
+^third_party/ashmem
+^third_party/boringssl
+^third_party/brotli
+^third_party/closure_compiler/closure_args.gni
+^third_party/closure_compiler/compile_js.gni
+^third_party/depot_tools/cpplint.py
+^third_party/depot_tools/download_from_google_storage.py
+^third_party/depot_tools/subprocess2.py
+^third_party/googletest/BUILD.gn
+^third_party/googletest/src/googletest/include/gtest/gtest_prod.h
+^third_party/icu/config.gni
+^third_party/lss/linux_syscall_support.h
+^third_party/modp_b64
+^third_party/nasm
+^third_party/perfetto/include/perfetto/tracing/traced_value_forward.h
+^third_party/protobuf/BUILD.gn
+^third_party/protobuf/proto_library.gni
+^third_party/protobuf/src
+^third_party/zlib
+^tools/cfi
+^tools/clang/scripts/update.py
+^tools/diagnosis
+^tools/grit
+^tools/gritsettings
+^tools/protoc_wrapper
+^tools/update_pgo_profiles.py
+^tools/win/DebugVisualizers
+^url
diff --git a/tools/list-openwrt.sh b/tools/list-openwrt.sh
new file mode 100644
index 0000000000..c93a3ab7da
--- /dev/null
+++ b/tools/list-openwrt.sh
@@ -0,0 +1,60 @@
+#!/bin/sh
+# $version can be 21.02 or 19.07.
+version=19.07.7
+if [ ! -d /tmp/openwrt ]; then
+  cd /tmp
+  git clone https://github.com/openwrt/openwrt.git
+  cd openwrt
+fi
+cd /tmp/openwrt
+git -c advice.detachedHead=false checkout v$version
+export TOPDIR=$PWD
+cd target/linux
+>targets.git
+for target in *; do
+  [ -d $target ] || continue
+  subtargets=$(make -C $target --no-print-directory DUMP=1 TARGET_BUILD=1 val.SUBTARGETS 2>/dev/null)
+  [ "$subtargets" ] || subtargets=generic
+  for subtarget in $subtargets; do
+    echo $(make -C $target --no-print-directory DUMP=1 TARGET_BUILD=1 SUBTARGET=$subtarget 2>/dev/null | egrep '^(Target:|Target-Arch-Packages:)' | cut -d: -f2) >>targets.git
+  done
+done
+
+targets=$(curl -s https://downloads.openwrt.org/releases/$version/targets/ | grep '<td class="n"><a href=' | cut -d'"' -f4 | sed 's,/,,')
+>targets.sdk
+for target in $targets; do
+  subtargets=$(curl -s https://downloads.openwrt.org/releases/$version/targets/$target/ | grep '<td class="n"><a href=' | cut -d'"' -f4 | sed 's,/,,')
+  for subtarget in $subtargets; do
+    arch=$(curl -s https://downloads.openwrt.org/releases/$version/targets/$target/$subtarget/profiles.json | grep arch_packages | cut -d'"' -f4)
+    echo $target/$subtarget $arch >>targets.sdk
+  done
+done
+
+cat >parse-targets.py <<EOF
+arch_by_target_git = {}
+arch_by_target_sdk = {}
+for line in open('targets.git'):
+    fields = line.split()
+    if not fields:
+        continue
+    arch_by_target_git[fields[0]] = fields[1]
+for line in open('targets.sdk'):
+    fields = line.split()
+    if len(fields) == 2:
+        if arch_by_target_git[fields[0]] != fields[1]:
+            raise Exception(line + ': wrong arch')
+        arch_by_target_sdk[fields[0]] = fields[1]
+    else:
+        arch_by_target_sdk[fields[0]] = ''
+for arch in sorted(set(arch_by_target_git.values())):
+    targets = []
+    for t in arch_by_target_git:
+        if arch_by_target_git[t] != arch:
+            continue
+        if t in arch_by_target_sdk:
+            targets.append(t)
+        else:
+            targets.append('~~' + t + '~~')
+    print('|', arch, '|?|', ' '.join(sorted(set(targets))), '|')
+EOF
+python3 parse-targets.py