Add warn and error functions to color warning and error output.

src/scripts/common.sh

 # Copyright (c) 2009 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Common constants for build scripts
 # This must evaluate properly for both /bin/bash and /bin/sh
 
 # All scripts should die on error unless commands are specifically excepted
 # by prefixing with '!' or surrounded by 'set +e' / 'set -e'.
 # TODO: Re-enable this once shflags is less prone to dying.
@@ skipping 206 matching lines @@
 is_whitelisted() {
   local file=$1
   local whitelist="$FLAGS_whitelist"
   test -f "$whitelist" || (echo "Whitelist file missing ($whitelist)" && exit 1)
 
   local checksum=$(md5sum "$file" | awk '{ print $1 }')
   local count=$(sed -e "s/#.*$//" "${whitelist}" | grep -c "$checksum" \
                 || /bin/true)
   test $count -ne 0
 }
+
+V_RED="\e[31m"
+V_YELLOW="\e[33m"
+
+function warn {
+  echo -e "${V_YELLOW}Warning..: $1${V_VIDOFF}"
+}
+
+function error {
+  echo -e "${V_RED}Error....: $1${V_VIDOFF}"
+}