Inherit EventTarget interface instead of duplicating its code

Source/core/dom/WebKitNamedFlow.idl

Index: Source/core/dom/WebKitNamedFlow.idl
diff --git a/Source/core/dom/WebKitNamedFlow.idl b/Source/core/dom/WebKitNamedFlow.idl
index 5a008bd3bd863564db2e0fcee7684ee616b0f7a2..68f2858700b427729862c8c38a883108b86084eb 100644
--- a/Source/core/dom/WebKitNamedFlow.idl
+++ b/Source/core/dom/WebKitNamedFlow.idl
@@ -30,23 +30,13 @@
 [
     NoInterfaceObject,
     EnabledAtRuntime=cssRegions,
-    EventTarget,
     ImplementedAs=NamedFlow,
     GenerateIsReachable=ownerNode
-] interface WebKitNamedFlow {
+] interface WebKitNamedFlow : EventTarget {
     readonly attribute DOMString name;
     readonly attribute boolean overset;
     readonly attribute long firstEmptyRegionIndex;
     NodeList getRegionsByContent(Node contentNode);
     NodeList getRegions();
     NodeList getContent();
-
-    // EventTarget interface
-    void addEventListener(DOMString type, 
-                          EventListener listener, 
-                          optional boolean useCapture);
-    void removeEventListener(DOMString type, 
-                             EventListener listener, 
-                             optional boolean useCapture);
-    [RaisesException] boolean dispatchEvent(Event event);
 };