Add a Via to DM that records into two pictures and draws using the second.

dm/DM.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "CrashHandler.h"
 #include "DMJsonWriter.h"
 #include "DMSrcSink.h"
@@ skipping 302 matching lines @@
         SINK("xps",  XPSSink);
     }
 #undef SINK
     return NULL;
 }
 
 static Sink* create_via(const char* tag, Sink* wrapped) {
 #define VIA(t, via, ...) if (0 == strcmp(t, tag)) { return new via(__VA_ARGS__); }
     VIA("pipe",      ViaPipe,          wrapped);
     VIA("serialize", ViaSerialization, wrapped);
+    VIA("2ndpic",    ViaSecondPicture, wrapped);
     VIA("tiles",     ViaTiles, 256, 256,               NULL, wrapped);
     VIA("tiles_rt",  ViaTiles, 256, 256, new SkRTreeFactory, wrapped);
 
     if (FLAGS_matrix.count() == 4) {
         SkMatrix m;
         m.reset();
         m.setScaleX((SkScalar)atof(FLAGS_matrix[0]));
         m.setSkewX ((SkScalar)atof(FLAGS_matrix[1]));
         m.setSkewY ((SkScalar)atof(FLAGS_matrix[2]));
         m.setScaleY((SkScalar)atof(FLAGS_matrix[3]));
@@ skipping 365 matching lines @@
     }
     return 0;
 }
 
 #if !defined(SK_BUILD_FOR_IOS)
 int main(int argc, char** argv) {
     SkCommandLineFlags::Parse(argc, argv);
     return dm_main();
 }
 #endif