Inherit EventTarget interface instead of duplicating its code

Source/core/loader/appcache/DOMApplicationCache.idl

Index: Source/core/loader/appcache/DOMApplicationCache.idl
diff --git a/Source/core/loader/appcache/DOMApplicationCache.idl b/Source/core/loader/appcache/DOMApplicationCache.idl
index c58f5e3e1f4f627bee40e32eac3be472defbf411..057f7b563cee37bf4f4284081e4ec485421ad2f5 100644
--- a/Source/core/loader/appcache/DOMApplicationCache.idl
+++ b/Source/core/loader/appcache/DOMApplicationCache.idl
@@ -25,9 +25,8 @@
 
 [
     NoInterfaceObject,
-    EventTarget,
     DoNotCheckConstants
-] interface DOMApplicationCache {
+] interface DOMApplicationCache : EventTarget {
     // update status
     const unsigned short UNCACHED = 0;
     const unsigned short IDLE = 1;
@@ -50,14 +49,5 @@
     attribute EventListener onupdateready;
     attribute EventListener oncached;
     attribute EventListener onobsolete;
-
-    // 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);
 };