Splitting up wait_for_device into two pieces

platform_tools/android/bin/adb_wait_for_charge

 #!/bin/bash
 #
-# Wait for the device to be ready to run tests.
+# Wait for the device to be charged enough for testing.
 
 SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 source $SCRIPT_DIR/android_setup.sh
 source $SCRIPT_DIR/utils/setup_adb.sh
 
 # Helper function used by get_battery_level. Parses the battery level from
 # dumpsys output.
 function _parse_battery_level {
   SPLIT=( $@ )
 
@@ skipping 42 matching lines @@
   if [ "$RV" != "-1" ]; then
     echo "$RV"
     return
   fi
 
   echo "Could not determine battery level!" 1>&2
   # Just exit to prevent hanging forever or failing the build.
   echo "0"
 }
 
-set -e
-
-# Wait for the device to be connected and fully booted.
-while [ "$($ADB $DEVICE_SERIAL shell getprop sys.boot_completed | tr -d '\r')" != "1" ]; do
-  echo "Waiting for the device to be connected and ready."
-  sleep 5
-done
-
 # Wait for battery charge.
 DESIRED_BATTERY_LEVEL=80
 CURRENT_BATTERY_LEVEL="$(get_battery_level)"
 while [ "${CURRENT_BATTERY_LEVEL}" -lt "${DESIRED_BATTERY_LEVEL}" ]; do
   echo "Battery level is ${CURRENT_BATTERY_LEVEL}; waiting to charge to ${DESIRED_BATTERY_LEVEL}"
   sleep 5
   CURRENT_BATTERY_LEVEL="$(get_battery_level)"
 done
 
-echo "Ready!"
+echo "Charged!"