[MSE] Fix GC with media_time past the last appended buffer timestamp

media/filters/source_buffer_stream.h

Index: media/filters/source_buffer_stream.h
diff --git a/media/filters/source_buffer_stream.h b/media/filters/source_buffer_stream.h
index deec40970ba53217343f32302db684e628dff651..3c727d7239154707cd692592674d982555071aa2 100644
--- a/media/filters/source_buffer_stream.h
+++ b/media/filters/source_buffer_stream.h
@@ -406,7 +406,8 @@ class MEDIA_EXPORT SourceBufferStream {
 
   // The timestamp of the last buffer appended to the media segment, set to
   // kNoDecodeTimestamp() if the beginning of the segment.
-  DecodeTimestamp last_appended_buffer_timestamp_;
+  DecodeTimestamp last_appended_buffer_timestamp_ = kNoDecodeTimestamp();
+  base::TimeDelta last_appended_buffer_duration_ = kNoTimestamp();
   bool last_appended_buffer_is_keyframe_ = false;
 
   // The decode timestamp on the last buffer returned by the most recent