Modify ivf reader functions

Modified ivf reader functions to facilitate the implementation and
testing of the tile list OBU.

Change-Id: I5a9d21b8387e2898cbdd4a06bac284b5e84035a8

common/video_reader.h

diff --git a/common/video_reader.h b/common/video_reader.h
index 3ee9a34..1eb3383 100644
--- a/common/video_reader.h
+++ b/common/video_reader.h
@@ -42,6 +42,11 @@
 // aom_video_reader_read_frame().
 const uint8_t *aom_video_reader_get_frame(AvxVideoReader *reader, size_t *size);
 
+// Returns the pts of the frame.
+int64_t aom_video_reader_get_frame_pts(AvxVideoReader *reader);
+// Return the reader file.
+FILE *aom_video_reader_get_file(AvxVideoReader *reader);
+
 // Fills AvxVideoInfo with information from opened video file.
 const AvxVideoInfo *aom_video_reader_get_info(AvxVideoReader *reader);