This change makes SurfaceHolder.setType(GPU) obsolete (it's now ignored).
Added an API to android_native_window_t to allow extending the functionality without ever breaking binary compatibility. This is used to implement the new set_usage() API. This API needs to be called by software renderers because the default is to use usage flags suitable for h/w.
we can't use a texture of 1/4th of the screen for the dim layer, because the mdp internal input resultion is alwyas integers and for very small blits of a couple pixels the scale factor can get way out of range, for instance for a 7 pixels source, the scale factor would be either 7 (7/1) or 3.5 (7/2) instead of 4 (7/1.75). This caused the mdp to fail in some cases and revert to software. we now always use a texture of the actual screen size, so the problem will never happen. This burns 300KB of pmem instead of 21KB. On devices with a larger screen we might want to use a smaller texture and tile it by hand.
