Emit Media Source codec names as media_log events.

media/base/video_decoder_config.cc

Index: media/base/video_decoder_config.cc
diff --git a/media/base/video_decoder_config.cc b/media/base/video_decoder_config.cc
index d2b6e410103e4a066c9b971a9376a30d3caa48c9..dcd0ffc69b47c55ab7d30165b7fce3e01238c130 100644
--- a/media/base/video_decoder_config.cc
+++ b/media/base/video_decoder_config.cc
@@ -9,6 +9,31 @@
 
 namespace media {
 
+// The names come from src/third_party/ffmpeg/libavcodec/codec_desc.c
+const char* VideoCodecName(VideoCodec video_codec) {
+  switch (video_codec) {
+    case kUnknownVideoCodec:
+      return "unknown";
+    case kCodecH264:
+      return "h264";
+    case kCodecVC1:
+      return "vc1";
+    case kCodecMPEG2:
+      return "mpeg2video";
+    case kCodecMPEG4:
+      return "mpeg4";
+    case kCodecTheora:
+      return "theora";
+    case kCodecVP8:
+      return "vp8";
+    case kCodecVP9:
+      return "vp9";
+    default:
+      NOTREACHED() << "Invalid VideoCodec: " << video_codec;
+      return "unknown";
+  }
+}
+
 VideoDecoderConfig::VideoDecoderConfig()
     : codec_(kUnknownVideoCodec),
       profile_(VIDEO_CODEC_PROFILE_UNKNOWN),