Do not call OnDecoderTiming before timing values are set.

webrtc/modules/video_coding/timing.h

Index: webrtc/modules/video_coding/timing.h
diff --git a/webrtc/modules/video_coding/timing.h b/webrtc/modules/video_coding/timing.h
index 85a3dd0ca0aa9d50dc1dc2e254a16df941ef4363..e7d2b1ffdd4c540cdc322cbee54bfced23920bc0 100644
--- a/webrtc/modules/video_coding/timing.h
+++ b/webrtc/modules/video_coding/timing.h
@@ -92,8 +92,9 @@ class VCMTiming {
   // certain amount of processing time.
   bool EnoughTimeToDecode(uint32_t available_processing_time_ms) const;
 
-  // Return current timing information.
-  void GetTimings(int* decode_ms,
+  // Return current timing information. Returns true if the first frame has been
+  // decoded, false otherwise.
+  bool GetTimings(int* decode_ms,
                   int* max_decode_ms,
                   int* current_delay_ms,
                   int* target_delay_ms,