Make adb_device_loop return if no devices

build/android/adb_device_functions.sh

 #!/bin/bash
 #
 # Copyright (c) 2012 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.
 #
 # A collection of functions useful for maintaining android devices
 
 
 # Run an adb command on all connected device in parallel.
@@ skipping 24 matching lines @@
 # adb_all
 # Usage: adb_device_loop 'command line to eval'
 adb_device_loop() {
   if [[ $# == 0 ]]; then
     echo "Intended for more complex one-liners that cannot be done with" \
         "adb_all."
     echo 'Usage: adb_device_loop "echo $DEVICE: $(adb root &&' \
         'adb shell cat /data/local.prop)"'
     return 1
   fi
-  local DEVICES=$(adb_get_devices -b)
+  local DEVICES=$(adb_get_devices)
+  if [[ -z $DEVICES ]]; then
+    return
+  fi
   # Do not change DEVICE variable name - part of api
   for DEVICE in $DEVICES; do
     DEV_TYPE=$(adb -s $DEVICE shell getprop ro.product.device | sed 's/\r//')
     echo "Running on $DEVICE ($DEV_TYPE)"
     ANDROID_SERIAL=$DEVICE eval "$*"
   done
 }
 
 # Erases data from any devices visible on adb.  To preserve a device,
 # disconnect it or:
@@ skipping 71 matching lines @@
 _adb_multi() {
   local DEVICES=$1
   local ADB_ARGS=$2
   (
     for DEVICE in $DEVICES; do
       adb -s $DEVICE $ADB_ARGS &
     done
     wait
   )
 }