core: add support for translucent volume panel

Add support for display the volume panel in translucent mode

Patchset 4: Make it depends to high-end graphics flag

Change-Id: I4f21a6cc88282789072a0e71ae696b754a5e083e
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>
QS: Fix up Wifi Display tile for screencasting and reenable it

Replace the Wifi Display code with MediaRouter/RemoteDisplay observers,
and turn let the controller manage the tile again

Change-Id: Iaf5c509ae078b9305d1d314ec76d44362beb025e
QS: Rename WiFiDisplay to RemoteDisplay

Change-Id: Iae8537482bc2c2a1beca71336a569bc5d4c16df5