check for null-pixelref

src/images/SkImageDecoder.cpp

Index: src/images/SkImageDecoder.cpp
diff --git a/src/images/SkImageDecoder.cpp b/src/images/SkImageDecoder.cpp
index 89a47054b2f05ea7369a7c1a3951daffff9fda6a..5b3cf325455f9fe3791893f65b4bf1bebdd52ef7 100644
--- a/src/images/SkImageDecoder.cpp
+++ b/src/images/SkImageDecoder.cpp
@@ -222,7 +222,9 @@ bool SkImageDecoder::DecodeFile(const char file[], SkBitmap* bm, SkColorType pre
     SkAutoTDelete<SkStreamRewindable> stream(SkStream::NewFromFile(file));
     if (stream.get()) {
         if (SkImageDecoder::DecodeStream(stream, bm, pref, mode, format)) {
-            bm->pixelRef()->setURI(file);
+            if (SkPixelRef* pr = bm->pixelRef()) {
+                pr->setURI(file);
+            }
             return true;
         }
     }