Do the codec string parsing for MSE in media, instead of Blink

Source/modules/mediasource/MediaSource.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 98 matching lines @@
     DECLARE_VIRTUAL_TRACE();
 
 private:
     explicit MediaSource(ExecutionContext*);
 
     void setReadyState(const AtomicString&);
     void onReadyStateChange(const AtomicString&, const AtomicString&);
 
     bool isUpdating() const;
 
-    PassOwnPtr<WebSourceBuffer> createWebSourceBuffer(const String& type, const Vector<String>& codecs, ExceptionState&);
+    PassOwnPtr<WebSourceBuffer> createWebSourceBuffer(const String& type, const String& codecs, ExceptionState&);
     void scheduleEvent(const AtomicString& eventName);
     void endOfStreamInternal(const WebMediaSource::EndOfStreamStatus, ExceptionState&);
 
     // Implements the duration change algorithm.
     // https://dvcs.w3.org/hg/html-media/raw-file/default/media-source/media-source.html#duration-change-algorithm
     void durationChangeAlgorithm(double newDuration);
 
     OwnPtr<WebMediaSource> m_webMediaSource;
     AtomicString m_readyState;
     OwnPtrWillBeMember<GenericEventQueue> m_asyncEventQueue;
     RawPtrWillBeWeakMember<HTMLMediaElement> m_attachedElement;
 
     Member<SourceBufferList> m_sourceBuffers;
     Member<SourceBufferList> m_activeSourceBuffers;
 
     bool m_isAddedToRegistry;
 };
 
 } // namespace blink
 
 #endif // MediaSource_h