Android Debug Bridge (adb) is a versatile command-line tool that lets you communicate with a device. The adb command facilitates a variety of device actions, such as installing and debugging apps, and it provides access to a Unix shell that you can use to run a variety of commands on a device. (from here)
In order to completely download the data of an application you can:
# From a root console
chmod777 /data/data/com.package
cp -r /data/data/com.package /sdcard Note: Using ADB attacker cannot obtain data directly by using command" adb pull /data/data/com.package". He is compulsorily required to move data to Internal storage and then he can pull that data.
adb pull "/sdcard/com.package"
You can use this trick to retrieve sensitive information like chrome passwords. For more info about this check the information a references provided here.