Only print error message in debug mode.

src/core/SkPicturePlayback.h

Index: src/core/SkPicturePlayback.h
diff --git a/src/core/SkPicturePlayback.h b/src/core/SkPicturePlayback.h
index 6acc0ae5088cf5724bb6a34143cec290b5cdb58d..b0af6942bcb1eb49fa00c398b024a92e07019df6 100644
--- a/src/core/SkPicturePlayback.h
+++ b/src/core/SkPicturePlayback.h
@@ -96,7 +96,9 @@ private:
     const SkBitmap& getBitmap(SkReader32& reader) {
         const int index = reader.readInt();
         if (SkBitmapHeap::INVALID_SLOT == index) {
+#ifdef SK_DEBUG
             SkDebugf("An invalid bitmap was recorded!\n");
+#endif
             return fBadBitmap;
         }
         return (*fBitmaps)[index];