Add minimal implementation of unprefixed MediaSource API that has feature parity with prefixed API

Source/core/dom/EventNames.h

 /*
  * Copyright (C) 2005, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Jon Shier (jshier@iastate.edu)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 146 matching lines @@
     macro(seeking) \
     macro(timeupdate) \
     macro(volumechange) \
     macro(waiting) \
     \
     macro(addtrack) \
     macro(cuechange) \
     macro(enter) \
     macro(exit) \
     \
+    macro(addsourcebuffer) \
+    macro(removesourcebuffer) \
+    macro(sourceopen) \
+    macro(sourceended) \
+    macro(sourceclose) \
+    macro(update) \
+    macro(updateend) \
+    macro(updatestart) \
     macro(webkitaddsourcebuffer) \
     macro(webkitremovesourcebuffer) \
     macro(webkitsourceopen) \
     macro(webkitsourceended) \
     macro(webkitsourceclose) \
     \
     macro(webkitkeyadded) \
     macro(webkitkeyerror) \
     macro(webkitkeymessage) \
     macro(webkitneedkey) \
@@ skipping 134 matching lines @@
     };
 
     inline EventNames& eventNames()
     {
         return threadGlobalData().eventNames();
     }
 
 }
 
 #endif