1. Now we are asking the user to grant permission to the service to enable
touch exploration only the first time this service is enabled. If the
service was uninstalled and then later installed we ask the user again.
This avoids the scenario in which rebooting the device or upgrading an
accessibility service leaves the device in a state in which the user
cannot interact with.
bug:6582088
Change-Id: I51d24e4892b3b48c9fb11dfb09ec1118502ba526