Glop support for indexed quads

bug:19014311
Change-Id: If35a873421b41cc4508b0d8ac1b4d900c9bb3717
diff --git a/libs/hwui/Glop.h b/libs/hwui/Glop.h
index 9150869..e2adff8 100644
--- a/libs/hwui/Glop.h
+++ b/libs/hwui/Glop.h
@@ -65,7 +65,7 @@
      * Stores mesh - vertex and index data.
      *
      * buffer objects and void*s are mutually exclusive
-     * indices are optional
+     * indices are optional, currently only GL_UNSIGNED_SHORT supported
      */
     struct Mesh {
         VertexAttribFlags vertexFlags;