Android bots: set battery threshold to 80%

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1559913003

Review URL: https://codereview.chromium.org/1559913003

diff --git a/platform_tools/android/bin/adb_wait_for_device b/platform_tools/android/bin/adb_wait_for_device
index 748ada3..a1f8c16 100755 (executable)
--- a/platform_tools/android/bin/adb_wait_for_device
+++ b/platform_tools/android/bin/adb_wait_for_device
@@ -72,7 +72,7 @@ while [ "$($ADB $DEVICE_SERIAL shell getprop sys.boot_completed | tr -d '\r')" !
 done
 
 # Wait for battery charge.
-DESIRED_BATTERY_LEVEL=100
+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}"