Fix chrome/test/data/safe_browsing/dmg/generate_test_data.sh to not silently fail.

chrome/test/data/safe_browsing/dmg/make_hfs.sh

 #!/bin/sh
 
 # Copyright 2015 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.
 
 # This script is used to generate an HFS file system with several types of
 # files of different sizes.
 
-set -e
+set -eu
 
 FILESYSTEM_TYPE="$1"
 RAMDISK_SIZE="$2"
 OUT_FILE="$3"
 
 VOLUME_NAME="SafeBrowsingDMG"
 UNICODE_FILENAME="Tĕsẗ 🐐 "
 
 if [[ ! $FILESYSTEM_TYPE ]]; then
   echo "Need to specify a filesystem type. See \`diskutil listfilesystems'."
@@ skipping 18 matching lines @@
 touch .metadata_never_index
 
 mkdir -p first/second/third/fourth/fifth
 
 pushd first
 pushd second
 pushd third
 pushd fourth
 pushd fifth
 
-dd if=/dev/random of=random bs=1 count=768
+dd if=/dev/random of=random bs=1 count=768 &> /dev/null
 
 popd   # fourth
 
 touch "Hello World"
 touch "hEllo wOrld"  # No-op on case-insensitive filesystem.
 
 popd  # third
 
 ln -s fourth/fifth/random symlink-random
 
 popd  # second
 
 echo "Poop" > "${UNICODE_FILENAME}"
 ditto --hfsCompression "${UNICODE_FILENAME}" goat-output.txt
 
 popd  # first
 
 ln "second/${UNICODE_FILENAME}" unicode_name
 
 popd  # volume root
 
 echo "This is a test HFS+ filesystem generated by" \
     "chrome/test/data/safe_browsing/dmg/make_hfs.sh." > README.txt
 
 popd  # Original PWD
 
 # Unmount the volume, copy the raw device to a file, and then destroy it.
 diskutil unmount ${RAMDISK_VOLUME}
-dd if=${RAMDISK_VOLUME} of="${OUT_FILE}"
+dd if=${RAMDISK_VOLUME} of="${OUT_FILE}" &> /dev/null
 diskutil eject ${RAMDISK_VOLUME}