Eradicate DisplayID.

DisplayDevices are now keyed of the wp<IBinder> the client uses.
DisplayID has now become DisplayType which is just used to identify
physical displays (as opposed to virtual displays such as wifi displays).

Change-Id: I0c5968f2c902dcd699a7e0afacf833ff070c12ea
diff --git a/services/surfaceflinger/LayerDim.h b/services/surfaceflinger/LayerDim.h
index fbfb2fb..06f312d 100644
--- a/services/surfaceflinger/LayerDim.h
+++ b/services/surfaceflinger/LayerDim.h
@@ -32,8 +32,7 @@
 class LayerDim : public LayerBaseClient
 {
 public:    
-                LayerDim(SurfaceFlinger* flinger, DisplayID display,
-                        const sp<Client>& client);
+                LayerDim(SurfaceFlinger* flinger, const sp<Client>& client);
         virtual ~LayerDim();
 
     virtual void onDraw(const sp<const DisplayDevice>& hw, const Region& clip) const;