Update DM JSON format.

dm/DMPDFTask.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "DMPDFTask.h"
 #include "DMPDFRasterizeTask.h"
 #include "DMUtil.h"
@@ skipping 68 matching lines @@
         SinglePagePDF pdf(fPicture->cullRect().width(), fPicture->cullRect().height());
         fPicture->playback(pdf.canvas());
         pdfData.reset(pdf.end());
     }
 
     SkASSERT(pdfData.get());
     if (rasterize) {
         this->spawnChild(SkNEW_ARGS(PDFRasterizeTask,
                                     (*this, pdfData->duplicate(), fRasterize)));
     }
+    const char* sourceType = fGM.get() ? "GM" : "SKP";
     this->spawnChild(SkNEW_ARGS(WriteTask,
-                                (*this, pdfData->duplicate(), ".pdf")));
+                                (*this, sourceType, pdfData->duplicate(), ".pdf")));
 }
 
 bool PDFTask::shouldSkip() const {
     if (!FLAGS_pdf) {
         return true;
     }
     if (fGM.get() && 0 != (fGM->getFlags() & skiagm::GM::kSkipPDF_Flag)) {
         return true;
     }
     return false;
 }
 
 }  // namespace DM