Make SkStream *not* ref counted.

src/pdf/SkPDFStream.h

Index: src/pdf/SkPDFStream.h
diff --git a/src/pdf/SkPDFStream.h b/src/pdf/SkPDFStream.h
index 586b2e8212d3d0706de6be028124d5b0a23c238e..cf9316ff1446d7af0288e844a6452fe68c90d3d5 100644
--- a/src/pdf/SkPDFStream.h
+++ b/src/pdf/SkPDFStream.h
@@ -93,10 +93,7 @@ private:
     // Mutex guards fState, fDataStream, and fSubstitute in public interface.
     SkMutex fMutex;
 
-    SkMemoryStream fMemoryStream;  // Used by fDataStream when
-                                   // fDataStream needs to be backed
-                                   // by SkData.
-    SkAutoTUnref<SkStreamRewindable> fDataStream;
+    SkAutoTDelete<SkStreamRewindable> fDataStream;
     SkAutoTUnref<SkPDFStream> fSubstitute;
 
     typedef SkPDFDict INHERITED;