surfaceflinger: Apply bugfixes to the correct hwc code paths

Changes I2deaf2ed101e8ea76708862a6bb67751b6078794 and
I1cb44389a05c9ec049d7f0d39c288feccb11a91c, both meant to deal
with corner-case layer states, were mistakenly merged into
the pre-1.0-hwc code paths. Move them to their intended locations

Change-Id: Idd6b3513cc36dda21b552eee97f9ea91793df18f
frameworks/native: Add support for Secure Display

- Add secure UI layers to primary and remove other layers from
  internal and external list for Secure Display usecase.
- Dont let secure UI layers to be captured on screen

Change-Id: Iebdad5c56247308604ee90928f6d6460a1f69279
Update HWUI config for xxhdpi/2GB devices

Change-Id: Ic9ba16b0360f2b755a1d23aa51eddc61beee2bac
Display: Add swaprect feature for MDP composition.

Add swaprect feature for MDP composition.
SwapRect is a SurfaceFlinger feature for selective composition
of only thedirty region.
* Existing SF does copying of the complete layer for every
 layer (in effect the full screen) whether or not the layer's
 information has changed (dirty region).
This is very inefficient use of compositing hardware (MDP/GPU).
* At the app level, we're doing dirty region rendering (App only
renders what is changed) using the feature "Dirty Region Rendering".
So, at the app level we know what has changed (dirty region) per
 layer. But SurfaceFlinger doesn't know this info and hence it's
 not able to use dirty region for selective composition and ends up
 compositing full screen.
* For SurfaceFlinger to composite only the dirty region
   1. It needs to know the dirty region (This needs to be passed
      down from the app)
   2. It needs to pass this info to the actual compositing hardware
     (MDP / GPU) so that the hw can do selective composition
* SWAPRECT feature needs to implement 1 & 2.
* 1 is common for all composition types whereas 2 is different
 for each composition type
This change implements 2 for MDP composition
* We've also added strong checks in the feature to make sure the
 feature kicks in only for the UX scenario's where performance
 improvement is expected and no functionality issue would arise.
To enable MDP Swaprect, setprop debug.sf.swaprect 1 and restart
framework.

Change-Id: Iac67acffcd4de1413cdbe0f15a278cc2cd54206f