Android 'soft' button bars

[Ben Rubinstein]

Some Android tablets (and for all I know, some Android phones) don't have 
standard home/menu/return buttons as physical buttons, but instead impose a 
soft version of them in a bar at the bottom of the screen (separate from the 
usual status bar at the top of the screen with clock, wifi, battery etc).

On some (eg original Kindle Fire) this is a separate bar at the bottom of the 
screen, but it hides and shows with the status bar, so we can use 
mobileHideStatusBar/mobileShowStatusBar to control it.

On others it doesn't. E.g. Samsung 7" tablet, and another I've seen, the 'soft 
buttons' bar is combined with the clock/wifi/settings etc status bar (I think 
this might be an Android 4.x thing) - and mobileHideStatusBar has no effect.

You don't get to hide the bar altogether, presumably because a rogue app could 
then effectively block a device; but there is a 'full screen' mode in which 
it's reduced to a minimum (on Kindle Fire, it shrinks and leaves just a 
disclosure triangle to reopen; on the Android 4.x devices I've seen, it fades 
to just a black bar with a few grey dots on it).  I've seen this in system 
apps (photo slideshow, video player) but also in some non-system apps.  Is 
there a way to access this mode in LC?

TIA,

Ben