diff --git a/src/build.sh b/src/build.sh
new file mode 100755
index 0000000000..85bcc4ead7
--- /dev/null
+++ b/src/build.sh
@@ -0,0 +1,82 @@
+#!/bin/sh
+set -e
+
+export TMPDIR="$PWD/tmp"
+rm -rf "$TMPDIR"
+mkdir -p "$TMPDIR"
+
+if [ "$1" = debug ]; then
+  out=out/Debug
+  flags="
+    is_debug=true
+    is_component_build=true"
+else
+  out=out/Release
+  flags="
+    is_official_build=true
+    exclude_unwind_tables=true
+    enable_resource_allowlist_generation=false
+    symbol_level=0"
+fi
+
+. ./get-sysroot.sh
+
+if [ "$CCACHE" ]; then
+  flags="$flags
+    cc_wrapper=\"$CCACHE\""
+fi
+
+flags="$flags"'
+  is_clang=true
+  use_sysroot=false
+
+  fatal_linker_warnings=false
+  treat_warnings_as_errors=false
+
+  enable_base_tracing=false
+  use_udev=false
+  use_aura=false
+  use_ozone=false
+  use_gio=false
+  use_gtk=false
+  use_platform_icu_alternatives=true
+  use_glib=false
+
+  disable_file_support=true
+  enable_websockets=false
+  use_kerberos=false
+  enable_mdns=false
+  enable_reporting=false
+  include_transport_security_state_preload_list=false
+  use_nss_certs=false
+'
+
+if [ "$WITH_SYSROOT" ]; then
+  flags="$flags
+    target_sysroot=\"//$WITH_SYSROOT\""
+fi
+
+if [ "$USE_AFDO" ]; then
+  flags="$flags"'
+    clang_sample_profile_path="//chrome/android/profiles/afdo.prof"'
+fi
+
+if [ "$ARCH" = "Darwin" ]; then
+  flags="$flags"'
+    enable_dsyms=false'
+fi
+
+if [ "$target_cpu" = "mipsel" -o "$target_cpu" = "mips64el" ]; then
+  flags="$flags"'
+    use_thin_lto=false
+    chrome_pgo_phase=0'
+fi
+
+rm -rf "./$out"
+mkdir -p out
+
+export DEPOT_TOOLS_WIN_TOOLCHAIN=0
+
+./gn/out/gn gen "$out" --args="$flags $EXTRA_FLAGS" --script-executable=$PYTHON
+
+ninja -C "$out" naive
diff --git a/src/get-clang.sh b/src/get-clang.sh
new file mode 100755
index 0000000000..ccfb23bbce
--- /dev/null
+++ b/src/get-clang.sh
@@ -0,0 +1,59 @@
+#!/bin/sh
+set -ex
+
+. ./get-sysroot.sh
+
+if [ "$SYSROOT_ARCH" -a ! -d ./"$WITH_SYSROOT/lib" ]; then
+  ./build/linux/sysroot_scripts/sysroot-creator.sh build "$SYSROOT_ARCH"
+fi
+
+if [ "$OPENWRT_FLAGS" ]; then
+  ./get-openwrt.sh
+fi
+
+if [ ! -d third_party/llvm-build/Release+Asserts/bin ]; then
+  mkdir -p third_party/llvm-build/Release+Asserts
+  clang_path="clang-$CLANG_REVISION.tgz"
+  clang_url="https://commondatastorage.googleapis.com/chromium-browser-clang/$WITH_CLANG/$clang_path"
+  curl "$clang_url" | tar xzf - -C third_party/llvm-build/Release+Asserts
+fi
+
+if [ "$USE_AFDO" -a ! -f chrome/android/profiles/afdo.prof ]; then
+  afdo_path=$(cat chrome/android/profiles/newest.txt)
+  afdo_url="https://storage.googleapis.com/chromeos-prebuilt/afdo-job/llvm/$afdo_path"
+  curl "$afdo_url" | bzip2 -cd >chrome/android/profiles/afdo.prof
+fi
+
+if [ "$WITH_PGO" -a ! -f chrome/build/pgo_profiles/"$PGO_PATH" ]; then
+  mkdir -p chrome/build/pgo_profiles
+  cd chrome/build/pgo_profiles
+  curl --limit-rate 10M -LO "https://storage.googleapis.com/chromium-optimization-profiles/pgo_profiles/$PGO_PATH"
+  cd ../../..
+fi
+
+if [ "$USE_SCCACHE" -a ! -f ~/.cargo/bin/sccache.exe ]; then
+  sccache_url="https://github.com/mozilla/sccache/releases/download/0.2.12/sccache-0.2.12-x86_64-pc-windows-msvc.tar.gz"
+  mkdir -p ~/.cargo/bin
+  curl -L "$sccache_url" | tar xzf - --strip=1 -C ~/.cargo/bin
+fi
+
+if [ ! -f gn/out/gn ]; then
+  gn_version=$(grep "'gn_version':" DEPS | cut -d"'" -f4)
+  mkdir -p gn/out
+  curl -L "https://chrome-infra-packages.appspot.com/dl/gn/gn/$WITH_GN-amd64/+/$gn_version" -o gn.zip
+  unzip gn.zip -d gn/out
+  rm gn.zip
+fi
+
+if [ "$USE_ANDROID_NDK" -a ! -d third_party/android_ndk ]; then
+  android_ndk_version=$(grep android_ndk.git DEPS | cut -d"'" -f10)
+  git clone --depth=1 --filter=blob:none --no-checkout https://chromium.googlesource.com/android_ndk.git third_party/android_ndk
+  cd third_party/android_ndk
+  git sparse-checkout init --cone
+  git sparse-checkout set sources/android/cpufeatures toolchains/llvm/prebuilt
+  git -c advice.detachedHead=false checkout "$android_ndk_version"
+  rm -rf .git
+  find toolchains -type f -regextype egrep \! -regex \
+    '.*(lib(atomic|gcc|gcc_real|compiler_rt-extras|android_support|unwind).a|crt.*o|lib(android|c|dl|log|m).so|usr/local.*|usr/include.*)' -delete
+  cd ../..
+fi
diff --git a/src/get-openwrt.sh b/src/get-openwrt.sh
new file mode 100755
index 0000000000..7919df382b
--- /dev/null
+++ b/src/get-openwrt.sh
@@ -0,0 +1,50 @@
+#!/bin/sh
+
+set -ex
+
+eval "$OPENWRT_FLAGS"
+
+sysroot=$PWD/out/sysroot-build/openwrt/$release/$arch
+if [ -d $sysroot/lib ]; then
+  exit 0
+fi
+mkdir -p $sysroot
+
+case "$arch" in
+arm_*) abi=musl_eabi;;
+*) abi=musl;;
+esac
+
+if [ "$subtarget" ]; then
+  SDK_PATH=openwrt-toolchain-$release-$target-${subtarget}_gcc-${gcc_ver}_${abi}.Linux-x86_64
+else
+  subtarget='generic'
+  SDK_PATH=openwrt-toolchain-$release-${target}_gcc-${gcc_ver}_${abi}.Linux-x86_64
+fi
+SDK_URL=https://downloads.openwrt.org/releases/$release/targets/$target/$subtarget/$SDK_PATH.tar.xz
+rm -rf $SDK_PATH
+curl $SDK_URL | tar xJf -
+cd $SDK_PATH
+full_root=toolchain-*_gcc-${gcc_ver}_${abi}
+cat >include.txt <<EOF
+./include
+./lib/*.o
+./lib/gcc/*/libgcc.a
+./lib/gcc/*/libgcc_eh.a
+./lib/libatomic.so*
+./lib/libatomic.a
+./lib/libc.so
+./lib/libc.a
+./lib/libdl.a
+./lib/ld-*
+./lib/libgcc_s.*
+./lib/libm.a
+./lib/libpthread.a
+./lib/libresolv.a
+./lib/librt.a
+./usr
+EOF
+tar cf - -C $full_root --hard-dereference . | tar xf - -C $sysroot --wildcards --wildcards-match-slash -T include.txt
+rm -rf include.txt
+cd ..
+rm -rf $SDK_PATH
diff --git a/src/get-sysroot.sh b/src/get-sysroot.sh
new file mode 100644
index 0000000000..81a1e53d8d
--- /dev/null
+++ b/src/get-sysroot.sh
@@ -0,0 +1,82 @@
+ARCH=$(uname)
+
+PYTHON=$(which python3 2>/dev/null || which python 2>/dev/null)
+mkdir -p third_party/llvm-build/Release+Asserts
+cd tools/clang/scripts
+CLANG_REVISION=$($PYTHON -c 'import update; print(update.PACKAGE_VERSION)')
+cd -
+echo $CLANG_REVISION >third_party/llvm-build/Release+Asserts/cr_build_revision
+
+eval "$EXTRA_FLAGS"
+case "$ARCH" in
+  Linux)
+    if which ccache >/dev/null 2>&1; then
+      export CCACHE_SLOPPINESS=time_macros
+      export CCACHE_BASEDIR="$PWD"
+      export CCACHE_CPP2=yes
+      CCACHE=ccache
+    fi
+    WITH_CLANG=Linux_x64
+    WITH_PGO=linux
+    WITH_GN=linux
+    if [ "$OPENWRT_FLAGS" ]; then
+      eval "$OPENWRT_FLAGS"
+      WITH_SYSROOT="out/sysroot-build/openwrt/$release/$arch"
+    elif [ "$target_os" = android ]; then
+      WITH_PGO=
+      USE_AFDO=y
+      USE_ANDROID_NDK=y
+      WITH_SYSROOT=
+      case "$target_cpu" in
+        x64) WITH_ANDROID_IMG=x86_64-24_r08;;
+        x86) WITH_ANDROID_IMG=x86-24_r08;;
+        arm64) WITH_ANDROID_IMG=arm64-v8a-24_r07;;
+        arm) WITH_ANDROID_IMG=armeabi-v7a-24_r07;;
+      esac
+    else
+      case "$target_cpu" in
+        x64) SYSROOT_ARCH=amd64;;
+        x86) SYSROOT_ARCH=i386;;
+        arm64) SYSROOT_ARCH=arm64;;
+        arm) SYSROOT_ARCH=armhf;;
+        mipsel) SYSROOT_ARCH=mipsel;;
+        mips64el) SYSROOT_ARCH=mips64el;;
+        riscv64) SYSROOT_ARCH=riscv64;;
+      esac
+      if [ "$SYSROOT_ARCH" ]; then
+        WITH_SYSROOT="out/sysroot-build/bullseye/bullseye_${SYSROOT_ARCH}_staging"
+      fi
+    fi
+  ;;
+  MINGW*|MSYS*)
+    ARCH=Windows
+    if [ -f "$HOME"/.cargo/bin/sccache* ]; then
+      export PATH="$PATH:$HOME/.cargo/bin"
+      CCACHE=sccache
+    fi
+    WITH_CLANG=Win
+    USE_SCCACHE=y
+    WITH_GN=windows
+    case "$target_cpu" in
+      x64) WITH_PGO=win64;;
+      *) WITH_PGO=win32;;
+    esac
+  ;;
+  Darwin)
+    if which ccache >/dev/null 2>&1; then
+      export CCACHE_SLOPPINESS=time_macros
+      export CCACHE_BASEDIR="$PWD"
+      export CCACHE_CPP2=yes
+      CCACHE=ccache
+    fi
+    WITH_CLANG=Mac
+    WITH_GN=mac
+    case "$target_cpu" in
+      arm64) WITH_PGO=mac-arm;;
+      *) WITH_PGO=mac;;
+    esac
+  ;;
+esac
+if [ "$WITH_PGO" ]; then
+  PGO_PATH=$(cat chrome/build/$WITH_PGO.pgo.txt)
+fi