Inherit EventTarget interface instead of duplicating its code

Source/core/css/FontLoader.idl

Index: Source/core/css/FontLoader.idl
diff --git a/Source/core/css/FontLoader.idl b/Source/core/css/FontLoader.idl
index 7e7842a6aa97be590bf85129e77a1fe42e59c51e..4e922c1ee52e7376b1c77cf44310578c9c22fbeb 100644
--- a/Source/core/css/FontLoader.idl
+++ b/Source/core/css/FontLoader.idl
@@ -32,9 +32,8 @@
     NoInterfaceObject,
     EnabledAtRuntime=fontLoadEvents,
     ActiveDOMObject,
-    EventTarget,
     GenerateIsReachable=document
-] interface FontLoader {
+] interface FontLoader : EventTarget {
 
     attribute EventListener onloading;
     attribute EventListener onloadingdone;
@@ -46,12 +45,4 @@
     void loadFont(Dictionary params);
     void notifyWhenFontsReady(VoidCallback callback);
     readonly attribute boolean loading;
-
-    void addEventListener(DOMString type,
-                          EventListener listener,
-                          optional boolean useCapture);
-    void removeEventListener(DOMString type,
-                             EventListener listener,
-                             optional boolean useCapture);
-    [RaisesException] boolean dispatchEvent(Event evt);
 };