[experimental] MR: add support for H264 recording

media/muxers/webm_muxer.cc

Index: media/muxers/webm_muxer.cc
diff --git a/media/muxers/webm_muxer.cc b/media/muxers/webm_muxer.cc
index 66c3f461c6bc02eec33992079a6258d6661082f6..3d863b980092c24057d2582b3b23457c78ae5812 100644
--- a/media/muxers/webm_muxer.cc
+++ b/media/muxers/webm_muxer.cc
@@ -74,7 +74,7 @@ WebmMuxer::WebmMuxer(VideoCodec codec,
                      bool has_video,
                      bool has_audio,
                      const WriteDataCB& write_data_callback)
-    : use_vp9_(codec == kCodecVP9),
+    : codec_(codec),
       video_track_index_(0),
       audio_track_index_(0),
       has_video_(has_video),
@@ -83,8 +83,8 @@ WebmMuxer::WebmMuxer(VideoCodec codec,
       position_(0) {
   DCHECK(has_video_ || has_audio_);
   DCHECK(!write_data_callback_.is_null());
-  DCHECK(codec == kCodecVP8 || codec == kCodecVP9)
-      << " Only Vp8 and VP9 are supported in WebmMuxer";
+  DCHECK(codec_ == kCodecVP8 || codec_ == kCodecVP9|| codec_ == kCodecH264)
+      << " Unsupported codec " << GetCodecName(codec_);
 
   segment_.Init(this);
   segment_.set_mode(mkvmuxer::Segment::kLive);
@@ -207,8 +207,13 @@ void WebmMuxer::AddVideoTrack(const gfx::Size& frame_size, double frame_rate) {
       reinterpret_cast<mkvmuxer::VideoTrack*>(
           segment_.GetTrackByNumber(video_track_index_));
   DCHECK(video_track);
-  video_track->set_codec_id(use_vp9_ ? mkvmuxer::Tracks::kVp9CodecId
-                                     : mkvmuxer::Tracks::kVp8CodecId);
+  if (codec_ == kCodecVP9)
+    video_track->set_codec_id(mkvmuxer::Tracks::kVp9CodecId);
+  else if (codec_ == kCodecVP8)
+    video_track->set_codec_id(mkvmuxer::Tracks::kVp8CodecId);
+  else
+    video_track->set_codec_id(mkvmuxer::Tracks::kVp8CodecId);
+
   DCHECK_EQ(0ull, video_track->crop_right());
   DCHECK_EQ(0ull, video_track->crop_left());
   DCHECK_EQ(0ull, video_track->crop_top());