Inherit EventTarget interface instead of duplicating its code

Source/modules/mediastream/MediaStream.h

Index: Source/modules/mediastream/MediaStream.h
diff --git a/Source/modules/mediastream/MediaStream.h b/Source/modules/mediastream/MediaStream.h
index fd83cbbe873a52af50a2fdc6741c98bfa3c96115..b11aae59d1b09779d1dbf6e25ad30c6871d807f9 100644
--- a/Source/modules/mediastream/MediaStream.h
+++ b/Source/modules/mediastream/MediaStream.h
@@ -40,7 +40,7 @@ namespace WebCore {
 
 typedef int ExceptionCode;
 
-class MediaStream : public RefCounted<MediaStream>, public ScriptWrappable, public URLRegistrable, public MediaStreamDescriptorClient, public EventTarget, public ContextLifecycleObserver {
+class MediaStream : public EventTarget, public RefCounted<MediaStream>, public ScriptWrappable, public URLRegistrable, public MediaStreamDescriptorClient, public ContextLifecycleObserver {
 public:
     static PassRefPtr<MediaStream> create(ScriptExecutionContext*);
     static PassRefPtr<MediaStream> create(ScriptExecutionContext*, PassRefPtr<MediaStream>);