Use sysroot for dpkg-shlibdeps when building debian package

chrome/installer/linux/debian/build.sh

Index: chrome/installer/linux/debian/build.sh
diff --git a/chrome/installer/linux/debian/build.sh b/chrome/installer/linux/debian/build.sh
index 7c6f14e3e68b57b2f68761146cb8a6f6705557b8..93261d4942ab27aed8eb8101c324aa16aa166a7a 100755
--- a/chrome/installer/linux/debian/build.sh
+++ b/chrome/installer/linux/debian/build.sh
@@ -162,7 +162,7 @@ verify_channel() {
 }
 
 process_opts() {
-  while getopts ":o:b:c:a:d:h" OPTNAME
+  while getopts ":s:o:b:c:a:d:h" OPTNAME
   do
     case $OPTNAME in
       o )
@@ -181,6 +181,9 @@ process_opts() {
       d )
         BRANDING="$OPTARG"
         ;;
+      s )
+        SYSROOT="$OPTARG"
+        ;;
       h )
         usage
         exit 0
@@ -264,7 +267,10 @@ touch debian/control
 # but it seems that we don't currently, so this is the most expediant fix.
 SAVE_LDLP=${LD_LIBRARY_PATH:-}
 unset LD_LIBRARY_PATH
-DPKG_SHLIB_DEPS=$(dpkg-shlibdeps -O "$BUILDDIR/chrome" | \
+if [[ -n ${SYSROOT:-} ]]; then
+  SHLIB_ARGS="--admindir=${SYSROOT}/var/lib/dpkg"
+fi
+DPKG_SHLIB_DEPS=$(dpkg-shlibdeps ${SHLIB_ARGS:-} -O "$BUILDDIR/chrome" | \
   sed 's/^shlibs:Depends=//')
 if [ -n "$SAVE_LDLP" ]; then
   LD_LIBRARY_PATH=$SAVE_LDLP