Fix last_range != range_for_next_append_ DCHECK in SourceBufferStream.

media/filters/source_buffer_stream.cc

Index: media/filters/source_buffer_stream.cc
diff --git a/media/filters/source_buffer_stream.cc b/media/filters/source_buffer_stream.cc
index 03de160b557314c2a27949745233728292dcc47c..bf867ca5163f45bbe0aa6da3b9f958c89443677f 100644
--- a/media/filters/source_buffer_stream.cc
+++ b/media/filters/source_buffer_stream.cc
@@ -391,7 +391,7 @@ void SourceBufferStream::OnNewMediaSegment(
                              media_segment_start_time)) {
     last_appended_buffer_timestamp_ = kNoTimestamp();
     last_appended_buffer_is_keyframe_ = false;
-  } else {
+  } else if (last_range != ranges_.end()) {
     DCHECK(last_range == range_for_next_append_);
   }
 }