add Webapp method and field

Change-Id: Ibe51b4b97f271cd5e3bd7f5dad20c1b7d7c60586
add isMiWifi method to WifiManager

N/A

Change-Id: Ifebc7f2fd761ccd2eb152b742e350fe9cecf148c
Signed-off-by: mochangming <mochangming@xiaomi.com>