Sync saved wifi passwords from defected mobile
There are multiple possible approaches:


If you have Google Cloud Backup activated on the "old" device, your WiFi passwords have been stored along (plain text, by the way). So starting with a new (or factory-reset) device, you should be asked on account creation whether to enable it here as well. Answering with "yes" will restore several things even from your old device, including WiFi passwords (for details, please see Google Backup: Multiple devices using the same account - what happens on Restore?)
If both devices have root access, you can use either a dedicated tool like WiFi Pass Recovery &amp; Backup, or straight go for a full-fledged solution like Titanium Backup
If at least the "old" device has root access, you can obtain your passwords from their configuration file directly. They are usually stored in /data/misc/wifi/wpa_supplicant.conf using plain-text.