Deprecate SkPicture::clone().

dm/DMPDFTask.h

 #ifndef DMPDFTask_DEFINED
 #define DMPDFTask_DEFINED
 
 #include "DMExpectations.h"
 #include "DMPDFRasterizeTask.h"
 #include "DMTask.h"
 #include "SkBitmap.h"
 #include "SkPicture.h"
 #include "SkString.h"
 #include "SkTemplates.h"
 #include "gm.h"
 
 namespace DM {
 
 // This task renders a GM or SKP using Skia's PDF backend.
 // If rasterizePdfProc is non-NULL, it will spawn a PDFRasterizeTask.
 class PDFTask : public CpuTask {
 public:
     PDFTask(const char*,
             Reporter*,
             TaskRunner*,
             skiagm::GMRegistry::Factory,
             RasterizePdfProc);
 
     PDFTask(Reporter*,
             TaskRunner*,
-            SkPicture*,
+            const SkPicture*,
             SkString name,
             RasterizePdfProc);
 
     virtual void draw() SK_OVERRIDE;
 
     virtual bool shouldSkip() const SK_OVERRIDE;
 
     virtual SkString name() const SK_OVERRIDE { return fName; }
 
 private:
     // One of these two will be set.
     SkAutoTDelete<skiagm::GM> fGM;
-    SkAutoTUnref<SkPicture> fPicture;
+    SkAutoTUnref<const SkPicture> fPicture;
 
     const SkString fName;
     RasterizePdfProc fRasterize;
 };
 
 }  // namespace DM
 
 #endif  // DMPDFTask_DEFINED