Fix crash in DM/SKPTask

dm/DMSKPTask.cpp

 #include "DMSKPTask.h"
 #include "DMUtil.h"
 #include "DMWriteTask.h"
 
 #include "SkCommandLineFlags.h"
 #include "SkPictureRecorder.h"
 
 DEFINE_bool(skr, true, "Test that SKPs draw the same when re-recorded with SkRecord backend.");
 
 namespace DM {
 
 // Test that an SkPicture plays back the same when re-recorded into an
 // SkPicture backed by SkRecord.
 class SkrComparisonTask : public CpuTask {
 public:
     SkrComparisonTask(const Task& parent, const SkPicture* picture, SkBitmap reference)
         : CpuTask(parent)
-        , fPicture(picture)
+        , fPicture(SkRef(picture))
         , fReference(reference)
         , fName(UnderJoin(parent.name().c_str(), "skr")) {}
 
     virtual bool shouldSkip() const SK_OVERRIDE { return !FLAGS_skr; }
     virtual SkString name() const SK_OVERRIDE { return fName; }
 
     virtual void draw() SK_OVERRIDE {
         SkPictureRecorder recorder;
         fPicture->draw(recorder.EXPERIMENTAL_beginRecording(fPicture->width(), fPicture->height()));
         SkAutoTDelete<const SkPicture> skrPicture(recorder.endRecording());
@@ skipping 21 matching lines @@
 void SKPTask::draw() {
     SkBitmap bitmap;
     AllocatePixels(kN32_SkColorType, fPicture->width(), fPicture->height(), &bitmap);
     DrawPicture(*fPicture, &bitmap);
 
     this->spawnChild(SkNEW_ARGS(WriteTask, (*this, bitmap)));
     this->spawnChild(SkNEW_ARGS(SkrComparisonTask, (*this, fPicture.get(), bitmap)));
 }
 
 }  // namespace DM