Add link to RFC2361 for WAV codecs as I always have a hard time finding said spec.

net/base/mime_util.cc

Index: net/base/mime_util.cc
diff --git a/net/base/mime_util.cc b/net/base/mime_util.cc
index 4dad7ad39ea0cc7c4b619f466cc09806471c83a1..60dd12518f092c964494ce73cefd96d03caf8f4d 100644
--- a/net/base/mime_util.cc
+++ b/net/base/mime_util.cc
@@ -258,6 +258,9 @@ static const char* const supported_media_types[] = {
 //
 // Refer to http://wiki.whatwg.org/wiki/Video_type_parameters#Browser_Support
 // for more information.
+//
+// The codecs for WAV are integers as defined in Appendix A of RFC2361:
+// http://tools.ietf.org/html/rfc2361
 static const char* const supported_media_codecs[] = {
 #if defined(GOOGLE_CHROME_BUILD) || defined(USE_PROPRIETARY_CODECS)
   "avc1",
@@ -268,7 +271,7 @@ static const char* const supported_media_codecs[] = {
 #endif
   "vorbis",
   "vp8",
-  "1"  // PCM for WAV.
+  "1"  // WAVE_FORMAT_PCM.
 };
 
 // Note: does not include javascript types list (see supported_javascript_types)