DM: add --key and --properties to PNG description field.

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 656 matching lines @@
         return false;
     }
 
     png_infop info = png_create_info_struct(png);
     if (!info) {
         png_destroy_write_struct(&png, &info);
         fclose(f);
         return false;
     }
 
+    SkString description;
+    description.append("Key: ");
+    for (int i = 0; i < FLAGS_key.count(); i++) {
+        description.appendf("%s ", FLAGS_key[i]);
+    }
+    description.append("Properties: ");
+    for (int i = 0; i < FLAGS_properties.count(); i++) {
+        description.appendf("%s ", FLAGS_properties[i]);
+    }
+    description.appendf("MD5: %s", md5);
+
     png_text text[2];
     text[0].key = (png_charp)"Author";
     text[0].text = (png_charp)"DM dump_png()";
     text[0].compression = PNG_TEXT_COMPRESSION_NONE;
     text[1].key = (png_charp)"Description";
-    text[1].text = (png_charp)md5;
+    text[1].text = (png_charp)description.c_str();
     text[1].compression = PNG_TEXT_COMPRESSION_NONE;
     png_set_text(png, info, text, 2);
 
     png_init_io(png, f);
     png_set_IHDR(png, info, (png_uint_32)w, (png_uint_32)h, 8,
                  PNG_COLOR_TYPE_RGB_ALPHA, PNG_INTERLACE_NONE,
                  PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
     png_write_info(png, info);
     for (int j = 0; j < h; j++) {
         png_bytep row = (png_bytep)(rgba.get() + w*j);
@@ skipping 379 matching lines @@
     }
     return 0;
 }
 
 #if !defined(SK_BUILD_FOR_IOS)
 int main(int argc, char** argv) {
     SkCommandLineFlags::Parse(argc, argv);
     return dm_main();
 }
 #endif