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/Layer.h b/services/surfaceflinger/Layer.h
index 22a441d..5e55887 100644
--- a/services/surfaceflinger/Layer.h
+++ b/services/surfaceflinger/Layer.h
@@ -66,8 +66,14 @@
     // LayerBase interface
     virtual void setGeometry(const DisplayDevice& hw,
             HWComposer::HWCLayerInterface& layer);
-    virtual void setPerFrameData(HWComposer::HWCLayerInterface& layer);
-    virtual void setAcquireFence(HWComposer::HWCLayerInterface& layer);
+    virtual void setPerFrameData(const DisplayDevice& hw,
+            HWComposer::HWCLayerInterface& layer);
+    virtual void setAcquireFence(const DisplayDevice& hw,
+            HWComposer::HWCLayerInterface& layer);
+    virtual void onLayerDisplayed(const DisplayDevice& hw,
+            HWComposer::HWCLayerInterface* layer);
+    virtual bool onPreComposition();
+    virtual void onPostComposition();
 
     virtual void onDraw(const DisplayDevice& hw, const Region& clip) const;
     virtual uint32_t doTransaction(uint32_t transactionFlags);
@@ -82,9 +88,6 @@
     // LayerBaseClient interface
     virtual wp<IBinder> getSurfaceTextureBinder() const;
 
-    virtual void onLayerDisplayed(HWComposer::HWCLayerInterface* layer);
-    virtual bool onPreComposition();
-
     // only for debugging
     inline const sp<GraphicBuffer>& getActiveBuffer() const { return mActiveBuffer; }
 
@@ -121,7 +124,6 @@
     bool mCurrentOpacity;
     bool mRefreshPending;
     bool mFrameLatencyNeeded;
-    bool mNeedHwcFence;
     int mFrameLatencyOffset;
 
     struct Statistics {