[Video] Disable bg optimization if avg keyframe distance is >10s

media/base/pipeline_status.h

Index: media/base/pipeline_status.h
diff --git a/media/base/pipeline_status.h b/media/base/pipeline_status.h
index 2899824665506cf7ffb9536a15d25661c42cfea8..8177231ea3a5261243e8c0a13cb1bc0e914156d5 100644
--- a/media/base/pipeline_status.h
+++ b/media/base/pipeline_status.h
@@ -59,6 +59,7 @@ struct PipelineStatistics {
   uint32_t video_frames_dropped = 0;
   int64_t audio_memory_usage = 0;
   int64_t video_memory_usage = 0;
+  int64_t video_keyframe_distance_average_ms = 0;
 };
 
 // Used for updating pipeline statistics; the passed value should be a delta