Inherit EventTarget interface instead of duplicating its code

Source/modules/websockets/WebSocket.idl

Index: Source/modules/websockets/WebSocket.idl
diff --git a/Source/modules/websockets/WebSocket.idl b/Source/modules/websockets/WebSocket.idl
index 7ebf523c60828eaab82d42f259ff6b578789b73d..e3324656a9eebebcb5766e124d24c9e813abe388 100644
--- a/Source/modules/websockets/WebSocket.idl
+++ b/Source/modules/websockets/WebSocket.idl
@@ -36,9 +36,8 @@
     Constructor(DOMString url, sequence<DOMString> protocols),
     Constructor(DOMString url, DOMString protocol),
     ConstructorRaisesException,
-    ConstructorCallWith=ScriptExecutionContext,
-    EventTarget
-] interface WebSocket {
+    ConstructorCallWith=ScriptExecutionContext
+] interface WebSocket : EventTarget {
     readonly attribute DOMString URL; // Lowercased .url is the one in the spec, but leaving .URL for compatibility reasons.
     readonly attribute DOMString url;
 
@@ -68,13 +67,4 @@
     [RaisesException] void send(DOMString data);
 
     [RaisesException] void close([Clamp] optional unsigned short code, optional DOMString reason);
-
-    // EventTarget interface
-    void addEventListener(DOMString type,
-                          EventListener listener,
-                          optional boolean useCapture);
-    void removeEventListener(DOMString type,
-                             EventListener listener,
-                             optional boolean useCapture);
-    [RaisesException] boolean dispatchEvent(Event evt);
 };