Add a dependency check for polymer-css-build to reproduce.sh

third_party/polymer/v1_0/reproduce.sh

 #!/bin/bash
 
 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Reproduces the content of 'components' and 'components-chromium' using the
 # list of dependencies from 'bower.json'. Downloads needed packages and makes
 # Chromium specific modifications. To launch the script you need 'bower' and
 # 'crisper' installed on your system.
 
 check_dep() {
   eval "$1" >/dev/null 2>&1
   if [ $? -ne 0 ]; then
     echo >&2 "This script requires $2."
     echo >&2 "Have you tried $3?"
     exit 1
   fi
 }
 
 check_dep "which npm" "npm" "visiting https://nodejs.org/en/"
 check_dep "which bower" "bower" "npm install -g bower"
 check_dep "which crisper" "crisper" "npm install -g crisper"
 check_dep "which uglifyjs" "uglifyjs" "npm install -g uglifyjs"
+check_dep "which polymer-css-build" "polymer-css-build" \
+    "npm install -g polymer-css-build"
 check_dep "which rsync" "rsync" "apt-get install rsync"
 check_dep "python -c 'import bs4'" "bs4" "apt-get install python-bs4"
 
 set -e
 
 pushd "$(dirname "$0")" > /dev/null
 
 rm -rf components
 rm -rf ../../web-animations-js/sources
 
@@ skipping 69 matching lines @@
 echo 'Creating GYP files for interfaces and externs...'
 ./generate_gyp.sh
 
 echo 'Vulcanizing dependent UIs...'
 python ../../../chrome/browser/resources/vulcanize.py
 
 popd > /dev/null
 
 echo 'Searching for unused elements...'
 "$(dirname "$0")"/find_unused_elements.py