webm_muxer_fix.patch is no longer needed

patches/webm_muxer_fix.patch

@@ -1,13 +0,0 @@
-diff --git a/media/muxers/webm_muxer.cc b/media/muxers/webm_muxer.cc
-index 9a4819a4..a089090 100644
---- a/media/muxers/webm_muxer.cc
-+++ b/media/muxers/webm_muxer.cc
-@@ -236,8 +236,6 @@ void WebmMuxer::AddVideoTrack(const gfx::Size& frame_size, double frame_rate) {
-   DCHECK_EQ(0ull, video_track->crop_bottom());
-   DCHECK_EQ(0.0f, video_track->frame_rate());
- 
--  video_track->set_default_duration(base::Time::kNanosecondsPerSecond /
--                                    frame_rate);
-   // Segment's timestamps should be in milliseconds, DCHECK it. See
-   // http://www.webmproject.org/docs/container/#muxer-guidelines
-   DCHECK_EQ(1000000ull, segment_.GetSegmentInfo()->timecode_scale());