The flat LiIon element in the mobile has nominal voltage 3.7 V and capacity 800-1000 mAh.
It is important, that the current limitation works, because in the oposite case
the charger or mobile could be destroyed.
In our case this condition is fulfiled.
So the charger works for the LiIon element as a current source.
The current should be more or less the same as defined by the producer.
In case of another charger of an other producer (5.6V / 150 mA)
till 1000 mA could be "pulled" out of the charger.