SF: Move LayerBE into it's own file

Move LayerBE related structures into a separate file, as prep
work for changes that will come in later and allow for sharing
structures between LayerBE and SurfaceFlingerBE

Test: Compiles
Change-Id: I36684d0e25e150a2dca6843073aa86991553e4f9
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 392acaa..bebd6a5 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -44,6 +44,7 @@
 #include <gui/LayerState.h>
 
 #include <gui/OccupancyTracker.h>
+#include <gui/BufferQueue.h>
 
 #include <hardware/hwcomposer_defs.h>
 
@@ -60,6 +61,7 @@
 #include "SurfaceInterceptor.h"
 #include "SurfaceTracing.h"
 #include "StartPropertySetThread.h"
+#include "LayerBE.h"
 
 #include "DisplayHardware/HWC2.h"
 #include "DisplayHardware/HWComposer.h"