cleanups in preparation of bigger changes

- fix typo drawForSreenshot misspelled
- get rid of DisplayDeviceBase
- removed unused or unneeded code
- always pass a DisplayDevice to Layer methods that are called
  on a per-display basis (to make it clear that this could be
  called more than once per composition).

Change-Id: Id948b7e09fe5c06db0e42d40d6ed75dd095c7f44
diff --git a/services/surfaceflinger/LayerBase.cpp b/services/surfaceflinger/LayerBase.cpp
index a92bf52..9d3a505 100644
--- a/services/surfaceflinger/LayerBase.cpp
+++ b/services/surfaceflinger/LayerBase.cpp
@@ -291,11 +291,13 @@
     layer.setVisibleRegionScreen(tr.transform(visibleRegion));
 }
 
-void LayerBase::setPerFrameData(HWComposer::HWCLayerInterface& layer) {
+void LayerBase::setPerFrameData(const DisplayDevice& hw,
+        HWComposer::HWCLayerInterface& layer) {
     layer.setBuffer(0);
 }
 
-void LayerBase::setAcquireFence(HWComposer::HWCLayerInterface& layer) {
+void LayerBase::setAcquireFence(const DisplayDevice& hw,
+        HWComposer::HWCLayerInterface& layer) {
     layer.setAcquireFenceFd(-1);
 }
 
@@ -314,7 +316,7 @@
     onDraw(hw, clip);
 }
 
-void LayerBase::drawForSreenShot(const DisplayDevice& hw)
+void LayerBase::drawForScreenShot(const DisplayDevice& hw)
 {
     setFiltering(true);
     onDraw( hw, Region(hw.bounds()) );