Log MediaSource parsing errors to the MediaLog so they can appear in chrome:media-internals.

media/base/media_log_event.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_BASE_MEDIA_LOG_EVENT_H_
 #define MEDIA_BASE_MEDIA_LOG_EVENT_H_
 
 #include "base/time.h"
 #include "base/values.h"
 
@@ skipping 50 matching lines @@
 
     // The audio renderer has been disabled.
     // params: none.
     AUDIO_RENDERER_DISABLED,
 
     // The extents of the sliding buffer have changed.
     // params: "buffer_start": <first buffered byte>.
     //         "buffer_current": <current offset>.
     //         "buffer_end": <last buffered byte>.
     BUFFERED_EXTENTS_CHANGED,
+
+    // Errors reported by Media Source Extensions code.
+    MEDIA_SOURCE_ERROR,
+    // params: "error": Error string describing the error detected.
   };
 
   int32 id;
   Type type;
   base::DictionaryValue params;
   base::Time time;
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_MEDIA_LOG_EVENT_H_