add Webapp method and field

Change-Id: I4994d7b7ee6b0eedd8d5d6512ce751f417aa68d6
add isMiWifi method to WifiManager

N/A

Change-Id: I6618adc166303c83d8d24ea30dac69adf6f3aa97
Signed-off-by: mochangming <mochangming@xiaomi.com>