Modified SurfaceFlinger to implment setActiveConfig and getActiveConfig.

This can be used to change the current display mode of the device.

Change-Id: Icdc3fb58389b861dc77b68102083da6f7a96eccb
Tested: None
(cherry picked from commit 2651fa94635a96d653038fb389a0dd827338f8d3)
6 files changed