Switch DDL rendering to be a Via in DM (take 2)

This will let us also render the GMs via DDLs.

TBR=mtklein@google.com
Change-Id: If7c2460d964822a6decc33cf5e8e685e67923127
Reviewed-on: https://skia-review.googlesource.com/116463
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
diff --git a/dm/DM.cpp b/dm/DM.cpp
index a6cb97f..0c4b15f 100644
--- a/dm/DM.cpp
+++ b/dm/DM.cpp
@@ -957,6 +957,8 @@
     VIA("tiles",     ViaTiles, 256, 256, nullptr,            wrapped);
     VIA("tiles_rt",  ViaTiles, 256, 256, new SkRTreeFactory, wrapped);
 
+    VIA("ddl",       ViaDDL, 3,            wrapped);
+
     if (FLAGS_matrix.count() == 4) {
         SkMatrix m;
         m.reset();