Inherit EventTarget interface instead of duplicating its code

Source/core/page/EventSource.h

Index: Source/core/page/EventSource.h
diff --git a/Source/core/page/EventSource.h b/Source/core/page/EventSource.h
index d22c2290f789f597560378b2008ca64f5decce10..1047c6bbae81581026e05c567e6fe009761f8081 100644
--- a/Source/core/page/EventSource.h
+++ b/Source/core/page/EventSource.h
@@ -49,7 +49,7 @@ class ResourceResponse;
 class TextResourceDecoder;
 class ThreadableLoader;
 
-class EventSource : public RefCounted<EventSource>, public ScriptWrappable, public EventTarget, private ThreadableLoaderClient, public ActiveDOMObject {
+class EventSource :  public EventTarget, public RefCounted<EventSource>, public ScriptWrappable, private ThreadableLoaderClient, public ActiveDOMObject {
     WTF_MAKE_FAST_ALLOCATED;
 public:
     static PassRefPtr<EventSource> create(ScriptExecutionContext*, const String& url, const Dictionary&, ExceptionCode&);