Move the key for handling keys from ScreenRecoveryUI to RecoveryUI, so
it can be used by devices without screens. Remove the UIParameters
struct and replace it with some new member variables in
ScreenRecoveryUI.
Change-Id: I4c0e659edcbedc0b9e86ed261ae4dbb3c6097414
Move all the functions in ui.c to be members of a ScreenRecoveryUI
class, which is a subclass of an abstract RecoveryUI class. Recovery
then creates a global singleton instance of this class and then invoke
the methods to drive the UI. We use this to allow substitution of a
different RecoveryUI implementation for devices with radically
different form factors (eg, that don't have a screen).
Change-Id: I7fd8b2949d0db5a3f47c52978bca183966c86f33
