diff --git a/scripts/transitive-deps.sh b/scripts/transitive-deps.sh
new file mode 100755
index 0000000..34e2ecf
--- /dev/null
+++ b/scripts/transitive-deps.sh
@@ -0,0 +1,483 @@
+#!/bin/bash
+
+set -eu
+
+# Copyright 2020 Google Inc. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Tool to evaluate the transitive closure of the ninja dependency graph of the
+# files and targets a given target depends on.
+#
+# i.e. the list of things that, if changed, could cause a change to a target.
+
+readonly me=$(basename "${0}")
+
+readonly usage="usage: ${me} {options} target [target...]
+
+Evaluate the transitive closure of files and ninja targets that one or more
+targets depend on.
+
+Dependency Options:
+
+  -(no)order_deps   Whether to include order-only dependencies. (Default false)
+  -(no)implicit     Whether to include implicit dependencies. (Default true)
+  -(no)explicit     Whether to include regular / explicit deps. (Default true)
+
+  -nofollow         Unanchored regular expression. Matching paths and targets
+                    always get reported. Their dependencies do not get reported
+                    unless first encountered in a 'container' file type.
+                    Multiple allowed and combined using '|'.
+                    e.g. -nofollow='*.so' not -nofollow='.so$'
+                    -nofollow='*.so|*.dex' or -nofollow='*.so' -nofollow='.dex'
+                    (Defaults to no matches)
+  -container        Unanchored regular expression. Matching file extensions get
+                    treated as 'container' files for -nofollow option.
+                    Multiple allowed and combines using '|'
+                    (Default 'apex|apk|zip|jar|tar|tgz')
+
+Output Options:
+
+  -(no)quiet        Suppresses progress output to stderr and interactive
+    alias -(no)q    prompts. By default, when stderr is a tty, progress gets
+                    reported to stderr; when both stderr and stdin are tty,
+                    the script asks user whether to delete intermediate files.
+                    When suppressed or not prompted, script always deletes the
+                    temporary / intermediate files.
+  -sep=<delim>      Use 'delim' as output field separator between notice
+                    checksum and notice filename in notice output.
+                    e.g. sep='\t'
+                    (Default space)
+  -csv              Shorthand for -sep=','
+  -directories=<f>  Output directory names of dependencies to 'f'.
+    alias -d        User '/dev/stdout' to send directories to stdout. Defaults
+                    to no directory output.
+  -notices=<file>   Output license and notice file paths to 'file'.
+    alias -n        Use '/dev/stdout' to send notices to stdout. Defaults to no
+                    license/notice output.
+  -projects=<file>  Output git project names to 'file'. Use '/dev/stdout' to
+    alias -p        send projects to stdout. Defaults to no project output.
+  -targets=<fils>   Output target dependencies to 'file'. Use '/dev/stdout' to
+    alias -t        send targets to stdout.
+                    When no directory, notice, project or target output options
+                    given, defaults to stdout. Otherwise, defaults to no target
+                    output.
+
+At minimum, before running this script, you must first run:
+$ source build/envsetup.sh
+$ lunch
+$ m nothing
+to setup the build environment, choose a target platform, and build the ninja
+dependency graph.
+"
+
+function die() { echo -e "${*}" >&2; exit 2; }
+
+# Reads one input target per line from stdin; outputs (isnotice target) tuples.
+#
+# output target is a ninja target that the input target depends on
+# isnotice in {0,1} with 1 for output targets believed to be license or notice
+function getDeps() {
+    (tr '\n' '\0' | xargs -0 -r "${ninja_bin}" -f "${ninja_file}" -t query) \
+    | awk -v include_order="${include_order_deps}" \
+        -v include_implicit="${include_implicit_deps}" \
+        -v include_explicit="${include_deps}" \
+        -v containers="${container_types}" \
+    '
+      BEGIN {
+        ininput = 0
+        isnotice = 0
+        currFileName = ""
+        currExt = ""
+      }
+      $1 == "outputs:" {
+        ininput = 0
+      }
+      ininput == 0 && $0 ~ /^\S\S*:$/ {
+        isnotice = ($0 ~ /.*NOTICE.*[.]txt:$/)
+        currFileName = gensub(/^.*[/]([^/]*)[:]$/, "\\1", "g")
+        currExt = gensub(/^.*[.]([^./]*)[:]$/, "\\1", "g")
+      }
+      ininput != 0 && $1 !~ /^[|][|]?/ {
+        if (include_explicit == "true") {
+          fileName = gensub(/^.*[/]([^/]*)$/, "\\1", "g")
+          print ( \
+              (isnotice && $0 !~ /^\s*build[/]soong[/]scripts[/]/) \
+              || $0 ~ /NOTICE|LICEN[CS]E/ \
+              || $0 ~ /(notice|licen[cs]e)[.]txt/ \
+          )" "(fileName == currFileName||currExt ~ "^(" containers ")$")" "gensub(/^\s*/, "", "g")
+        }
+      }
+      ininput != 0 && $1 == "|" {
+        if (include_implicit == "true") {
+          fileName = gensub(/^.*[/]([^/]*)$/, "\\1", "g")
+          $1 = ""
+          print ( \
+              (isnotice && $0 !~ /^\s*build[/]soong[/]scripts[/]/) \
+              || $0 ~ /NOTICE|LICEN[CS]E/ \
+              || $0 ~ /(notice|licen[cs]e)[.]txt/ \
+          )" "(fileName == currFileName||currExt ~ "^(" containers ")$")" "gensub(/^\s*/, "", "g")
+        }
+      }
+      ininput != 0 && $1 == "||" {
+        if (include_order == "true") {
+          fileName = gensub(/^.*[/]([^/]*)$/, "\\1", "g")
+          $1 = ""
+          print ( \
+              (isnotice && $0 !~ /^\s*build[/]soong[/]scripts[/]/) \
+              || $0 ~ /NOTICE|LICEN[CS]E/ \
+              || $0 ~ /(notice|licen[cs]e)[.]txt/ \
+          )" "(fileName == currFileName||currExt ~ "^(" containers ")$")" "gensub(/^\s*/, "", "g")
+        }
+      }
+      $1 == "input:" {
+        ininput = 1
+      }
+    '
+}
+
+# Reads one input directory per line from stdin; outputs unique git projects.
+function getProjects() {
+    while read d; do
+        while [ "${d}" != '.' ] && [ "${d}" != '/' ]; do
+            if [ -d "${d}/.git/" ]; then
+                echo "${d}"
+                break
+            fi
+            d=$(dirname "${d}")
+        done
+    done | sort -u
+}
+
+
+if [ -z "${ANDROID_BUILD_TOP}" ]; then
+    die "${me}: Run 'lunch' to configure the build environment"
+fi
+
+if [ -z "${TARGET_PRODUCT}" ]; then
+    die "${me}: Run 'lunch' to configure the build environment"
+fi
+
+readonly ninja_file="${ANDROID_BUILD_TOP}/out/combined-${TARGET_PRODUCT}.ninja"
+if [ ! -f "${ninja_file}" ]; then
+    die "${me}: Run 'm nothing' to build the dependency graph"
+fi
+
+readonly ninja_bin="${ANDROID_BUILD_TOP}/prebuilts/build-tools/linux-x86/bin/ninja"
+if [ ! -x "${ninja_bin}" ]; then
+    die "${me}: Cannot find ninja executable expected at ${ninja_bin}"
+fi
+
+
+# parse the command-line
+
+declare -a targets # one or more targets to evaluate
+
+include_order_deps=false    # whether to trace through || "order dependencies"
+include_implicit_deps=true  # whether to trace through | "implicit deps"
+include_deps=true           # whether to trace through regular explicit deps
+quiet=false                 # whether to suppress progress
+
+projects_out=''             # where to output the list of projects
+directories_out=''          # where to output the list of directories
+targets_out=''              # where to output the list of targets/source files
+notices_out=''              # where to output the list of license/notice files
+
+sep=" "                     # separator between md5sum and notice filename
+
+nofollow=''                 # regularexp must fully match targets to skip
+
+container_types=''          # regularexp must full match file extension
+                            # defaults to 'apex|apk|zip|jar|tar|tgz' below.
+
+use_stdin=false             # whether to read targets from stdin i.e. target -
+
+while [ $# -gt 0 ]; do
+    case "${1:-}" in
+      -)
+        use_stdin=true
+      ;;
+      -*)
+        flag=$(expr "${1}" : '^-*\(.*\)$')
+        case "${flag:-}" in
+          order_deps)
+            include_order_deps=true;;
+          noorder_deps)
+            include_order_deps=false;;
+          implicit)
+            include_implicit_deps=true;;
+          noimplicit)
+            include_implicit_deps=false;;
+          explicit)
+            include_deps=true;;
+          noexplicit)
+            include_deps=false;;
+          csv)
+            sep=",";;
+          sep)
+            sep="${2?"${usage}"}"; shift;;
+          sep=)
+            sep=$(expr "${flag}" : '^sep=\(.*\)$');;
+          q) ;&
+          quiet)
+            quiet=true;;
+          noq) ;&
+          noquiet)
+            quiet=false;;
+          nofollow)
+            case "${nofollow}" in
+              '')
+                nofollow="${2?"${usage}"}";;
+              *)
+                nofollow="${nofollow}|${2?"${usage}"}";;
+            esac
+            shift
+          ;;
+          nofollow=*)
+            case "${nofollow}" in
+              '')
+                nofollow=$(expr "${flag}" : '^nofollow=\(.*\)$');;
+              *)
+                nofollow="${nofollow}|"$(expr "${flag}" : '^nofollow=\(.*\)$');;
+            esac
+          ;;
+          container)
+            container_types="${container_types}|${2?"${usage}"}";;
+          container=*)
+            container_types="${container_types}|"$(expr "${flag}" : '^container=\(.*\)$');;
+          p) ;&
+          projects)
+            projects_out="${2?"${usage}"}"; shift;;
+          p=*) ;&
+          projects=*)
+            projects_out=$(expr "${flag}" : '^.*=\(.*\)$');;
+          d) ;&
+          directores)
+            directories_out="${2?"${usage}"}"; shift;;
+          d=*) ;&
+          directories=*)
+            directories_out=$(expr "${flag}" : '^.*=\(.*\)$');;
+          t) ;&
+          targets)
+            targets_out="${2?"${usage}"}"; shift;;
+          t=*) ;&
+          targets=)
+            targets_out=$(expr "${flag}" : '^.*=\(.*\)$');;
+          n) ;&
+          notices)
+            notices_out="${2?"${usage}"}"; shift;;
+          n=*) ;&
+          notices=)
+            notices_out=$(expr "${flag}" : '^.*=\(.*\)$');;
+          *)
+            die "Unknown flag ${1}";;
+        esac
+      ;;
+      *)
+        targets+=("${1:-}")
+      ;;
+    esac
+    shift
+done
+
+
+# fail fast if command-line arguments are invalid
+
+if [ ! -v targets[0] ] && ! ${use_stdin}; then
+    die "${usage}\n\nNo target specified."
+fi
+
+if [ -z "${projects_out}" ] \
+  && [ -z "${directories_out}" ] \
+  && [ -z "${targets_out}" ] \
+  && [ -z "${notices_out}" ]
+then
+    targets_out='/dev/stdout'
+fi
+
+if [ -z "${container_types}" ]; then
+  container_types='apex|apk|zip|jar|tar|tgz'
+fi
+
+# showProgress when stderr is a tty
+if [ -t 2 ] && ! ${quiet}; then
+    showProgress=true
+else
+    showProgress=false
+fi
+
+# interactive when both stderr and stdin are tty
+if ${showProgress} && [ -t 0 ]; then
+    interactive=true
+else
+    interactive=false
+fi
+
+
+readonly tmpFiles=$(mktemp -d "${TMPDIR}.tdeps.XXXXXXXXX")
+if [ -z "${tmpFiles}" ]; then
+    die "${me}: unable to create temporary directory"
+fi
+
+# The deps files contain unique (isnotice target) tuples where
+# isnotice in {0,1} with 1 when ninja target 'target' is a license or notice.
+readonly oldDeps="${tmpFiles}/old"
+readonly newDeps="${tmpFiles}/new"
+readonly allDeps="${tmpFiles}/all"
+
+if ${use_stdin}; then # start deps by reading 1 target per line from stdin
+  awk '
+    NF > 0 {
+      print ( \
+          $0 ~ /NOTICE|LICEN[CS]E/ \
+          || $0 ~ /(notice|licen[cs]e)[.]txt/ \
+      )" "gensub(/\s*$/, "", "g", gensub(/^\s*/, "", "g"))
+    }
+  ' > "${newDeps}"
+else # start with no deps by clearing file
+  : > "${newDeps}"
+fi
+
+# extend deps by appending targets from command-line
+for idx in "${!targets[*]}"; do
+    isnotice='0'
+    case "${targets[${idx}]}" in
+      *NOTICE*) ;&
+      *LICEN[CS]E*) ;&
+      *notice.txt) ;&
+      *licen[cs]e.txt)
+        isnotice='1';;
+    esac
+    echo "${isnotice} 1 ${targets[${idx}]}" >> "${newDeps}"
+done
+
+# remove duplicates and start with new, old and all the same
+sort -u < "${newDeps}" > "${allDeps}"
+cp "${allDeps}" "${newDeps}"
+cp "${allDeps}" "${oldDeps}"
+
+# report depth of dependenciens when showProgress
+depth=0
+
+# 1st iteration always unfiltered
+filter='cat'
+while [ $(wc -l < "${newDeps}") -gt 0 ]; do
+    if ${showProgress}; then
+        echo "depth ${depth} has "$(wc -l < "${newDeps}")" targets" >&2
+        depth=$(expr ${depth} + 1)
+    fi
+    ( # recalculate dependencies by combining unique inputs of new deps w. old
+        sh -c "${filter}" < "${newDeps}" | cut -d\  -f3- | getDeps
+        cat "${oldDeps}"
+    ) | sort -u > "${allDeps}"
+    # recalculate new dependencies as net additions to old dependencies
+    set +e
+    diff "${oldDeps}" "${allDeps}" --old-line-format='' --new-line-format='%L' \
+      --unchanged-line-format='' > "${newDeps}"
+    set -e
+    # apply filters on subsequent iterations
+    case "${nofollow}" in
+      '')
+        filter='cat';;
+      *)
+        filter="egrep -v '^[01] 0 (${nofollow})$'"
+      ;;
+    esac
+    # recalculate old dependencies for next iteration
+    cp "${allDeps}" "${oldDeps}"
+done
+
+# found all deps -- clean up last iteration of old and new
+rm -f "${oldDeps}"
+rm -f "${newDeps}"
+
+if ${showProgress}; then
+    echo $(wc -l < "${allDeps}")" targets" >&2
+fi
+
+if [ -n "${targets_out}" ]; then
+    cut -d\  -f3- "${allDeps}" | sort -u > "${targets_out}"
+fi
+
+if [ -n "${directories_out}" ] \
+  || [ -n "${projects_out}" ] \
+  || [ -n "${notices_out}" ]
+then
+    readonly allDirs="${tmpFiles}/dirs"
+    (
+        cut -d\  -f3- "${allDeps}" | tr '\n' '\0' | xargs -0 dirname
+    ) | sort -u > "${allDirs}"
+    if ${showProgress}; then
+        echo $(wc -l < "${allDirs}")" directories" >&2
+    fi
+
+    case "${directories_out}" in
+      '')        : do nothing;;
+      *)
+        cat "${allDirs}" > "${directories_out}"
+      ;;
+    esac
+fi
+
+if [ -n "${projects_out}" ] \
+  || [ -n "${notices_out}" ]
+then
+    readonly allProj="${tmpFiles}/projects"
+    egrep -v '^out[/]' "${allDirs}" | getProjects > "${allProj}"
+    if ${showProgress}; then
+        echo $(wc -l < "${allProj}")" projects" >&2
+    fi
+
+    case "${projects_out}" in
+      '')        : do nothing;;
+      *)
+        cat "${allProj}" > "${projects_out}"
+      ;;
+    esac
+fi
+
+case "${notices_out}" in
+  '')        : do nothing;;
+  *)
+    readonly allNotice="${tmpFiles}/notices"
+    egrep '^1' "${allDeps}" | cut -d\  -f3- | egrep -v '^out/' > "${allNotice}"
+    cat "${allProj}" | while read proj; do
+        for f in LICENSE LICENCE NOTICE license.txt notice.txt; do
+            if [ -f "${proj}/${f}" ]; then
+                echo "${proj}/${f}"
+            fi
+        done
+    done >> "${allNotice}"
+    if ${showProgress}; then
+      echo $(cat "${allNotice}" | sort -u | wc -l)" notice targets" >&2
+    fi
+    readonly hashedNotice="${tmpFiles}/hashednotices"
+    ( # md5sum outputs checksum space indicator(space or *) filename newline
+        sort -u "${allNotice}" | tr '\n' '\0' | xargs -0 -r md5sum 2>/dev/null
+      # use sed to replace space and indicator with separator
+    ) > "${hashedNotice}"
+    if ${showProgress}; then
+        echo $(cut -d\  -f2- "${hashedNotice}" | sort -u | wc -l)" notice files" >&2
+        echo $(cut -d\  -f1 "${hashedNotice}" | sort -u | wc -l)" distinct notices" >&2
+    fi
+    sed 's/^\([^ ]*\) [* ]/\1'"${sep}"'/g' "${hashedNotice}" | sort > "${notices_out}"
+  ;;
+esac
+
+if ${interactive}; then
+    echo -n "$(date '+%F %-k:%M:%S') Delete ${tmpFiles} ? [n] " >&2
+    read answer
+    case "${answer}" in [yY]*) rm -fr "${tmpFiles}";; esac
+else
+    rm -fr "${tmpFiles}"
+fi