Add change to enable getting safe build of chrome

src/scripts/build_platform_packages.sh

Index: src/scripts/build_platform_packages.sh
===================================================================
--- src/scripts/build_platform_packages.sh	(revision 315)
+++ src/scripts/build_platform_packages.sh	(working copy)
@@ -12,6 +12,7 @@
 assert_inside_chroot
 
 # Flags
+DEFINE_boolean stable $FLAGS_FALSE "Build with stable version of browser."
 
 # Parse command line
 FLAGS "$@" || exit 1
@@ -36,6 +37,12 @@
                       wpa_supplicant xscreensaver/xscreensaver-5.08 \
                       xserver-xorg-core xserver-xorg-video-intel"
 
+if [ $FLAGS_stable -eq $FLAGS_TRUE ]
+then
+  # Passed to copy_chrome_zip.sh to get stable version of the browser
+  export GET_STABLE_CHROME=1
+fi
+
 # Build third_party packages first, since packages and libs depend on them.
 for i in $THIRD_PARTY_PACKAGES
 do