Fix MSE GC, make it less aggressive, more spec-compliant

media/filters/source_buffer_range.h

Index: media/filters/source_buffer_range.h
diff --git a/media/filters/source_buffer_range.h b/media/filters/source_buffer_range.h
index 71d3618d92b3a013959b7cddf2fdbbaa830d76a8..13ba873cc20518333d8327eb8d7f3804509da954 100644
--- a/media/filters/source_buffer_range.h
+++ b/media/filters/source_buffer_range.h
@@ -124,6 +124,8 @@ class SourceBufferRange {
       DecodeTimestamp start_timestamp, DecodeTimestamp end_timestamp,
       size_t bytes_to_free, DecodeTimestamp* end_removal_timestamp);
 
+  bool FirstGOPEarlierThanMediaTime(DecodeTimestamp media_time) const;
+
   // Indicates whether the GOP at the beginning or end of the range contains the
   // next buffer position.
   bool FirstGOPContainsNextBufferPosition() const;