Enhanced performance in ContactTileView due to alpha layer.

Change-Id: I3f8eaddf674ffe9c1b6c5267e1e3050c8308d783
diff --git a/src/com/android/contacts/list/ContactTileView.java b/src/com/android/contacts/list/ContactTileView.java
index ad711cf..e4abff3 100644
--- a/src/com/android/contacts/list/ContactTileView.java
+++ b/src/com/android/contacts/list/ContactTileView.java
@@ -41,6 +41,7 @@
 
     public ContactTileView(Context context, AttributeSet attrs) {
         super(context, attrs);
+        setLayerType(View.LAYER_TYPE_HARDWARE, null);
     }
 
     @Override