sand: Add servo overlay for sand

Inherit reef servo overlay configuration.

BUG=chrome-os-partner:62200
TEST=None

Change-Id: Ifae0c22c0362a802cf687a7fd621bb66b731cbc3
Reviewed-on: https://chromium-review.googlesource.com/440469
Commit-Ready: YH Lin <yueherngl@chromium.org>
Tested-by: Katherine Hsieh <Katherine.Hsieh@quantatw.com>
Reviewed-by: YH Lin <yueherngl@chromium.org>
Reviewed-by: Katherine Hsieh <Katherine.Hsieh@quantatw.com>
diff --git a/servo/data/servo_sand_overlay.xml b/servo/data/servo_sand_overlay.xml
new file mode 100644
index 0000000..a4b1377
--- /dev/null
+++ b/servo/data/servo_sand_overlay.xml
@@ -0,0 +1,5 @@
+<root>
+  <include>
+    <name>servo_reef_overlay.xml</name>
+  </include>
+</root>