calculate wether we filter on a per-display basis

Change-Id: I79d80b432b20b3d02428da19add464ac1e2b9378
diff --git a/services/surfaceflinger/LayerBase.h b/services/surfaceflinger/LayerBase.h
index 9994994..0df41ca 100644
--- a/services/surfaceflinger/LayerBase.h
+++ b/services/surfaceflinger/LayerBase.h
@@ -197,7 +197,7 @@
     /**
      * needsLinearFiltering - true if this surface's state requires filtering
      */
-    virtual bool needsFiltering() const { return mNeedsFiltering; }
+    virtual bool needsFiltering(const sp<const DisplayDevice>& hw) const;
 
     /**
      * isSecure - true if this surface is secure, that is if it prevents